Want to build a 300 H&H first timer

Hello all, new to this site but "regular" on CASTBOOLITS and 24HRCAMPFIRE was suggested I post my question here.
I've always wanted a 300 H&H just cause I like "classic" cartridges. I realize there may be "better" cartridges out there but whats the fun in that?
I've got my eye on an ugly beat up model 11 (I think) in 300 Win Mag with detachable box magazine.
Thinking this would be a good candidate for my conversion?? What about 30/06??
I see Shilen makes barrels...anyone use these?? any other makers better/worse??
Wondering how cartridges would feed from magazine. H&H about .025 longer than an '06 or 300 WinMag.
Bolt facr probably need to be changed if it were '06 but thinkin 300 Mag bolt face might work.
I understand the bolt face/head can be ordered?? from whom??
Go/NOGO gauges needed// Brownells?
Any help or tips would be appreciated. Thinking it would be fun project.
Thanks