Dan,
I cannot comment about Magnepan with McIntosh tube amps but I can share the following experience.
I have been driving Maggies 1.7i with an integrated PrimaLuna Dialogue Two (KT88s) rated 38 Wpc in UL mode, to good satisfaction/musicality.
My good friend has been driving his pair with an integrated Doge 5 (EL34s) rated 30 Wrms/ch in Class AB mode, also to his liking.
I also found a good match driving them with a Pass Labs XA30.8 rated 30 Wpc in Class A.
But I got the most satisfying result - to my ears - driving the Maggies with a higher powered Class AB stereo amp combined with a tube preamp.
In my case the Goldmund Telos 280 rated 215 Wrms/ch (dynamics, detail) with the Nagra Jazz or Ayon Stealth (midrange, involvement).
I'm assuming the MC1502 rated 150 Wpc should have enough juice for the .7s
Maybe an alternative worth considering, at a substantially lower price point, would be the integrated hybrid MA352 rated 200 Wpc? Maybe a nice way to get the best of both worlds?
Magnepan make very good speakers, there are many ways to enjoy them, have a great journey with yours
All above ratings into 8 ohm.