Steve... couldn't answer that because I just finished the thing yesterday, and the sides were a new idea... my own. If they don't work out, my bad. However, I don't think it will be a problem. One thing I didn't point out in the pix was that while the obvious tendency is to clamp the riser on the bridge, nothing stops you from sliding the whole thing down a bit to get where you need to work past the riser.
There's a possibility my rig may be longer than it would be best at, too. I think John Strunk's was a bit shorter. I thought about shorter but went with this length because I didn't want to end up working on too long a piece past the brace, in case it would flex.
My scrapers and tools should get here from 3 Rivers this week and I'll be working on the bow a bit... then we'll see.
Dick in Seattle