Man I can't believe I missed this posting... but it looks like you got a really good plan and should be able to hit the mid 40's no problem at all. when I'm ready to tune one of these engines I always take out the good plug, or just don't use a good one until it's broken in and tuned. If you need a good cheap set of "throw away" plugs that are light years better than those cheap ones that come in the kits, you can get teh Autolite #275 plugs in 4 packs at most auto parts stores for around $8 so if you foul one out, you can just replace with a new one once you're ready to do the plug chops for a really accurate plug reading. Then when I'm done with the plug chops, these plugs get a bath in the Berryman B9 Chem Dip for a few hours, then a spray down with carb and choke or brake cleaner, they'll still have some staining on them but they'll work like new. After the plug chops are done then it's time to spring for an irridium plug, but if you dirty or foul the irridium, the same "acid bath" mentioned above will clean them up nicely too.
I also like the Carnny frames and they do tend to hold up really well, you can always strip tehm down and go over every weld with some nickel/silver brazing rods if you see any iffy welds anywhere or need a quick way to gusset up the frame at the critical points. The nickel/silver rods can be hard to find and they're expensive, but they are just about as strong as a good weld and you can do teh job with mapp gas if no welding equipment is available.
I see you're also doing an excellent job shaving off all the unnecessary weight on the rotating compunents, you're right, every little bit helps here...
