They don’t feel like SPDs just because the shoes don’t have the full rubber on them. I guess it’s more like road cleats (never used them), with the bulb in the front of the shoe and the heel real low.
The only tip, really, is to use the shorter bolts that come with it. Unlike SPD shoes, you’re going to bang into the carbon sole, if you don’t, and crack/scratch the sole.
I would also replace the adapters, when changing cleats. I don’t think the rubber bit lasts as long as a shoe’s rubber outer sole, if you walk around much.
There are also no cleat covers, AFAIK, so going on hardwood or a painted garage is probably not a good idea. The cleat seems to make contact easier with the flooring, than with a proper SPD shoe.
But, if you want road shoes with the SPD interface, I don’t have any problems with these. Power transfer/flex seems as good as my proper carbon sole’d SPD shoes. It’s probably lighter too, with less rubber.