I only found this out recently, but there are two types of SPD cleat if it might help. One is a single-action turn the heel out to unclip, the other is a multi-release action where you can either turn the heel out or pull your heel up to unclip. The two types are SH51 which is single action and SH56 is the multi-release one.
I think your pedal spacers are a good idea anyway. What you don't want to be doing is forcing your foot into a position where it doesn't drop to naturally. If you do that, you'll just be transferring unnatural load to your ankle, knee or hip and it'll cause longer term problems. Higher Q mountain bike cranks may also help because the outward bend in the crank will give you a bit more midfoot/heel clearance. With a square taper setup you'll also be able to run a wider crank axle which will also buy you a few extra mm heel clearance from the stays.
I only found this out recently, but there are two types of SPD cleat if it might help. One is a single-action turn the heel out to unclip, the other is a multi-release action where you can either turn the heel out or pull your heel up to unclip. The two types are SH51 which is single action and SH56 is the multi-release one.
I think your pedal spacers are a good idea anyway. What you don't want to be doing is forcing your foot into a position where it doesn't drop to naturally. If you do that, you'll just be transferring unnatural load to your ankle, knee or hip and it'll cause longer term problems. Higher Q mountain bike cranks may also help because the outward bend in the crank will give you a bit more midfoot/heel clearance. With a square taper setup you'll also be able to run a wider crank axle which will also buy you a few extra mm heel clearance from the stays.