Probably not applicable but I use the 1/4 x 0.200" stuff
StewMac sells but only in my bass necks (the 24" long stuff & 2 of them) & run them parallel with the taper of the neck. My six stringers I usually like to laminate up the neck (even if it's all the same timber I'll still glue at least two bits together) so feel that they're fairly strong & stable as is, touch wood (

) I haven't had a neck warp on me so far. But that's just how I do things, I'm not advocating
not putting CF in, it's probably good insurance if you are at all worried.