i understand that argument, but the intended reigon is generally the final arbiter, when something else like graphical and/or music glitches doesn't give it away.
playing a pal developed game that was never released as NTSC on c64 is like playing a pal game on an ntsc nes. it allows an unfairly fast time, because the PAL game is usually optimized for 50 fps.
that's what i believe.
Now fairly often a game does get released without changes. an example of this is c64 tetris. the music plays faster in the USA, but the game still plays fine (if a little faster) because it was officially released in the USA, the game should be tased on that video standard. the game was most definitely originally PAL, but it was released on NTSC in stores (i know, i bought it!). Not that this is a particularly good game to TAS. In fact, its' a horrible choice. :)
At times the "play at hardest level" guidelines and "play at native video standard" guideline conflict for computer software. and that's not getting into bugfixed cracks (very common on this platform) Some pathological examples.
1) Exile. the only version that works on NTSC is a crack. in this case the original is not deliberately incompatible with NTSC, it just is. There are many such games that there is no original that functions on NTSC.
2) Encounter by novagen. the game actually runs fine on NTSC, except that all PAL originals are coded to deliberately crash on NTSC c64s. only the synapse software import runs fine. You need the .g64 of the synapse original to work on NTSC, as there is no other one that works. If the PAL one is fixed to work on NTSC, it's harder than the actual NTSC version, which was made easier to account for the frame rate difference (and broke the demo in the process. Me and another Hokuto Force member actually fixed this in our crack, which plays the demo at PAL difficulty, but the main game at NTSC difficulty.). So the hardest versions are cracks of PAL versions played on NTSC, since the original pal one won't start on NTSC. confused yet? :)
Also, when a game has advanced graphical effects, the PAL version can be faster, because the NTSC version has to drop to 30 fps due to lack of CPU time. The simplest example of this is bubble bobble c64, where due to not enough cpu time the intro story screen runs at half rate on NTSC, and actually plays FASTER on PAL, though the main game is slower. Bu tusually it's a NTSC-FIX version that was never released commercially because it was a crack.
This is a really thorny issue. Best is to ask what the intended region is, and if it was ever actually released in an NTSC territory.
On the other hand, TAS don't compete with RTA runs. and TAS at 50 hz is no different for TAS at 60 hz in difficulty. so that's a pretty good argument for NTSC if the game runs on both.
Also, there's the case of a PAL and NTSC version being totally different. in this cas,e you MUST play the PAL one on PAL, and the NTSC one on NTSC. for example there are two different bionic commando versions. they are in fact different programs, with different graphics and sound. a tAS of one would not obsolete the other. in this case, even if the PAL one runs on ntsc, it's wrong to play it, because it's not the game that the NTSC region got. If we allow that, then we have to allow TASing PAL nes games at 60hz, which is known to be NOT okay.
also in the absence of a cart, loading times can be different. if say you don't have a 1541, but an MSD drive, and the game doesn't have a fastloader, it will load faster on the MSD drive. which means a faster completion time. on the other hand if the game has an optimized fastloader for 1541, and kernal fallack, it will load faster on the 1541 drive. Using a fastload cart on real hardware can get the game to load faster. you can even use .d64 images on real hardware with an SD2IEC. Or you can use a snapshot cart to get a game to load faster on real hardware.
It's a huge can of worms, when there isn't a handy cart version. also theres' non true drive emulation. this can someimes work on original and get them to load lightning fast. but that's proably not okay... is it?
Th real issue is that the c64 isn't really a fixed platform, even though it doesn't have any way to upgrade the base hardware. it can have peripherals. we have to declare a certain official hardware platform to be used fo TASing. Generally it's a final rev kernal c64 (yes there is more than one "OS" rom for the computer) with a 1541 drive and a datasette, with true device emulation, and either a cart, a .tap, a .d64, or a .g64 image. .t64 is right out (it loads way too fast, even though certain original swill convert to it). so are .prg and .p00, though they are the fastest loading in most modern emulators.
and disk emulation still isn't fully accurate, which affects timing. The position of the disk platter before it's inserted affects load time. The exact RPM of the drive (not always even totally constant) affects speed. .TAP and .crt can be considered fully accurate.
so here's my best compromise rules.
If the game is not an arcade onversion, and has no covers of songs, and the game does not glithc more on NTSC< use that.
if the game glitches more on one video standard, use the other.
if the game is a conversion of an arcade, an the music is only right on one video standard, use that. SAme if the game covers a non game tune. use the one that plays hte song back at the right speed.
But if it's an original tune, it's okay to run the pal on on NTSC, as long as it doesn't glitch, and there is no separate NTSC release that's tuned differently.
A decision also needs to be made for sure on fast loaders, which someone trying to speedrun the game would certainly use on real hardware.