Don't think anyone is going to be able to give you a direct answer. The type and length of engine mount, and carb will differ with different builds. Also the routing you decide on will dictate the length. At the point that you are ready to install them you will have to figure the length for your particular application. If you are at that point, fine. If not don't even think about it until you are ready for them. Many things change during a build. Location of exhaust etc. Take if one step at a time.
Congrats on the build. I think you will be quite happy with the kit. Supercrow has given you a couple of things to think about and I will add a couple more.
I have ordered my carb heat, cabin heat, and mixture cables from Vans. These are long and you cut to fit. The throttle does depend. If memory serves correct (and it may not) the PA12 cable is a little longer than the stock SC cable (we are talking ordering from Univare). With a stock mount and 0-320 the SC cable works fine. If you are going 0-360, and I see you are, the longer PA12 cable seems to work better.