I have a 722, and it's on its third 700 SA stock. Refitting the correct 700 stock to a 721/722 takes about 30 minutes of hand work. I've succeeded at it, so can assure you than anyone capable of slicing bologna without hurting themselves can get it done.
The bolt gap is pretty minor, and can be filled in with bedding compound on a synthetic stock, if it bothers you.
Were I looking to meet your criteria, I would buy a factory synthetic (tupperware) LA ADL stock. You will need to also buy a 700 trigger guard and magazine box. You may or may not need to file the magazine box to fit properly -- that's just a matter of assemble and see. Many people discount the tupperware stocks, but I've had one on my .35 Whelen for about 15 years, and it shoots under MOA and has held up extremely well.
Tupperware is easy and economical, and if you decide to upgrade later, you're not out much.
"The more you run over a dead cat, the flatter it gets."
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"It ain't foot-pounds that kills stuff -- it's broken body parts."