If you're using anything over 30W, in my opinion, you're not going to get the optimum tone. Unless you have a studio that's REALLY big and quite isolated. And even then, why bother?
I confess, I've never understood when guys (even metal guys) come into the studio with 100W heads and ask how best to get the ideal "tone." In my experience (which includes a number of "name" shops, as well as my own place), you can do the same thing with (much) smaller combos.
But I'm sidestepping the original poster's question.
If you want to get the tone of your amp "to tape," get the guitar and amp sound you desire (however loud, with whatever wattage, in the live room) and stick a dynamic mic in front of it. It's that simple. Sorry. Most engineers don't entertain questions of loudness and wattage. They ask the player to get the tone he wants and then devise the best means (given the room and the studio's resources—mics and preamps and such) to capture it. That's his job, after all.
Candidly, I don't know a recording application more devoid of difficulty (strange effects, aside) as recording electric guitar. Put a 57
in front of the speaker, on-axis, half-way between the cone and the periphery of the cone, 3-6" out from the grill. That should be, at a minimum, workable, if not fantastic. Move the mic around (different distances, different angles), if the initial settings aren't fabulous. Or add a ribbon (Royer R-121 or R-122) or LDC (Gefell UMT70S is my favorite) or a "different" dynamic (421 or SM7) if you want. Adjust for phase. Blend to taste. Play around. Have fun.
But a lowly 57
on the right amp in a "decent" room should totally work. Assuming your "guy" can play.
Sorry for the preamble. Best of luck.