The standard colemak layout has been fixed which is I think one of it's advantages. It's not contanstly being tinkered with.
If it was being tinkered with constantly I personally wouldn't have given it a chance.

There are people on this forum that have modified Colemak for their own particular issues and maybe one of them can help you make a slight modification.   Moving the space bar for general use on a standard keyboard would just be nuts.   You might consider one of those specialized keyboards. If you are having medical issues that would seem to be a worthwhile investment.

I already have a bit of a mental hiccup when I switch back to QWERTY (I tend to tap the caps lock once or twice, too), and if the spacebar was anywhere else I doubt I'd be able to switch back and forth at all.  That's just a bit too drastic, in my opinion.  Also, as mentioned above, the layout is locked now, so there won't be any updates in the future.

I am one of the people that keyboard samurai mention - I use a variant I call Colemak-B that swaps 'J' and 'B', moves the '-' one key closer to my pinkie, and swaps the shifted states of '?' and '/' so that all the sentence-terminating punctuation is unshifted (except the exclamation point, which I very rarely use).  I use a Mac, so my keyboard tweaking software is Ukelele, but I don't know if it allows remapping of system keys like the spacebar (it didn't allow tweaking of the caps lock key, for example).

Feel free to play around with the layout, but don't expect Shai to make any more changes to the layout, especially significant ones like moving the space bar.  He's earned support for his layout due largely to his caution and the subtlety of his changes.  He was very careful swapping 'R' and 'S' because it broke the muscle memory for Command-S (Save).  Breaking the muscle memory on the space bar is not something that is going to happen.