When I first started with my home-made CNC, I had issues being my Z travel was only 4", and I routinely had to cut 7/4 stock, leaving me less than .5" of safe Z. If I didn't pay attention to the initial Z or safe Z height, then sometimes the Z ran into the carriage going up and if I didn't watch what was going on, m piece was done! Now I make a habit of checking everything before starting the job, even just glancing at the G Code to make sure everything's cool.
I too was bitten by the spped bug. Theough I can rapid all axes over 400ipm, my table was shaking uncontrollably. I lowered the rapids to 165 on the X and Y, and 120 on the Z. Less craziness, got to help with the cut.
To lessen the chances of warpage, I try to use exclusively kild dried quartersawn stock, that I have aclimated in my at least a year. Even then, sometimes the wood is not fully dry. Sometimes for the sake of expediency some woods are dried too fast in the kiln, and they actuallly case-harden. Then when you cut, you get to the moist center! Sometimes because the way the wood is stored it's the complete opposite. The only way to know for sure is to have it in as controlled environment as possible, but of course this is not always practical. As a small guitar builder, I've accumulated wood over the years, and by the time I have a project to do, the wood has been in my possession for a few years. Of course, quartersawn may be out of the question if you want quilt or birdseye maple.
I've learned to use any mechanical means of clamping as possible. I never trust double stick tape. I use it sometimes when aligning a piece, but then I always use blocks, or cut a fixture out of scrap. I've made a few just for guitar bodies. Up until recently I was cutting necks manually, but now I'm making fixtures for them as well.