For a 10 minute run, it doesn't matter if you use PRG0 or PRG1. I did a little comparision between WIPs. The top left being your one done with the block zip at the start, your one on the bottom left (I needed to alter what you did slightly to get this position), the current published run on the top right and my WIP on the bottom-right.
It's probably too difficult to spot any major differences between the picures. So I've decided to blow them up, I also put the red dots to make comparisions easier.
Compared to the current published run on the top right, my WIP was 2 pixels ahead, your one was 5 and your one with the zip is 9 pixels ahead. Mario moves at 6 pixels a frame when at full running speed so there is 1.5 frames gained. Sadly when I intially tried to do the mushroom glitch I encountered all the lag problems, this is where all the problems came from gaining the frame in the last WIP, but I'm convinced there is a way to avoid it, we just have to test various different aproaches until one works. That way we can jump a frame earlier thus make the mushroom appear a frame earlier and successfully get the mushroom.