My 14" Delta/Rockwell has the old heavyweight castings and the riser block didn't affect the rigidity but the 3/4hp wasn't cutting it. Priced a 1 hp and when I went to pick it up it was out of stock so they gave me a 1 1/2 hp for the same price. But I think Chestnut's right I would step up to a bigger machine rather than put too much in your current saw.
1/32 spacers ! Consider me quite impressed, 1/16 isn't easy. Your repairs turned out well, that's the true measure of skill ,well just short of perfection but that rarely happens until you've built 4 or 5 of the same piece.
I thought that the lines on my arms were not great and now i'm looking at the arms and think i was crazy for my thoughts of a few weeks ago. There are bigger fish to fry on this project, chasing perfect line son the laminations would be futile.
Get a new saw. The riser blocks will get you capacity at the cost of the frame not being as rigid and the cut quality not being as potentially good as the current 14" models. I also think that for how much you could probably sell your saw if need be the upgrade cost might not be terrible.
an 18bx would be an awesome saw no doubt about that.