I just scanned the thread and may have missed something
to set the timing, the best way after reversing the admission is to go back to the kit instructions but you are now doing things 180 degrees off.
This should get you very close to there. The Ruby has simple timing which means there is lap in both forward and reverse so there will always be a lag in timing causing poor performance. You can advance the timing in forward by rotating the eccentric in that direction but it will retard it in reverse. You can actually get to the point where it runs wonderfully in forward and not at all in reverse. Get it so it barely runs in reverse and it will perform well in forward.
8% grade is double what the max recommended is. You will definitely need RC and will need to use the Johnson bar to slow it down if you go down something that steep. Pulling back on the throttle wont brake it at all.