You'll get used to it – flipping a pedal with a toe clip is a lot trickier, and presumably that has become second nature to you?
Tips-wise – obviously start with one already in, pedal off to a speed where the bike rides itself (without worrying about clipped-ness), then put your non-clipped foot on the vacant pedal and get the feel/sound of metal on metal, then its just a question of getting the toe end in first.
I wouldn't bother reducung the tension, since it doesn't particualrly make it much easier to get clipped in and it will compromise the point of having spds in the first place.
Like anything, take a quiet five minutes of solid practice every day for a week and you'll be a pro in no time.