I'll be printing 35mm to 4x5, with the bulk being 35mm to 6x9, so I'll need multiple mixing chambers for any heads I use.

I'm going to hedge my bets and try multiple heads. I've got a lead on a used Dichro 45s head. I will keep an eye out for Minolta 45a heads in the range you mentioned. There are a couple on eBay now, but they are closer to $300. With used color heads and enlargers going so cheap these days, I can afford to play the field. I printed with a condenser head and filter drawer a long time ago. That was pretty tediuous. I'll skip that option this time around.