I agree with you needing two saws...........at least . I just got a used 394 for milling. There is no way I would want to limb with that thing even with a 20" bar. My first though when I read your post was a modded 372, but I have to say I only have a muffler mod on my 372 and the stock 394 was better to mill with. I have never ran a fully modded 372 so I don't know how it would compare. But two saw would be the ticket. I know Jeff Sikkema had some used saws of all sizes. Give him a shout.
Doug
Doug