I'm no help here but out of the 3 cartridges you mentioned I'd have to go
6-06. I contacted Mr. Forbes about turning a 270 into a 6.5x284 and he said no "it won't feed worth a crap" Then again I'd smack myself silly to have a 9.3 that he put together. Most people say that their CLR 270 shoot very well. With that said and I didn't mind a .277, I'd buy the stock and bolt it together without bedding and see what it does. If that combo don't make you smile I'd send it in for the barrel twisted right and turned the contour that suites and have HIM do a full length bedding. Most anyone can bed a action but to get a clean full bedding job takes a few practice runs.

Want To Buy;
Form die for a 7mm Mashburn Super.
.284 Hornady AMax 162gr.
.224 Hornady AMax 75gr.
22-250 bushing die
Bushing die that will work with the 7mm Mashburn Super
A couple Glock 42 380ACP mags