Wilwoods and Brembos generally have a ready-made adaptor/caliper carrier that bolts to the hub, to mount the caliper.
Unless you're going to get the modifications completed by a professional engineering company (e.g.
www.futbus.com ), to make the Mazda calipers fit I am extremely unlikely to get excited about a set of calipers that look like they might fit if you hold them up and squint a bit.
Brakes, being a key safety item are something I'm quite keen to be able to just bolt up as a complete set up, rather than chop about with a grinder and drill to make 'sort of' fit.
As I don't believe you've got any dependants you're less likely to worry about nailing whatever hacked about brakes you want to your car, so you crack on.
My 280mm set up is just fine.
