camshaft and crank keys

Just about to put the pistons in my 73 340 i am building but before i do i want to make sure i understand the camshaft keys or offset keys and the woodruff key portion of the build.

I installed a new comp cams 268xe cam. to my understanding there s 4 degrees advance built into the cam. So because of this should i use a 4 degree advance cam key and a 4 degree advance woodruff key. I read everything that came with the cam/timing set and it doesn't really say if you are supposed to or not. The timing set mentioned it (0degree 4 degree advance and 4 degree retard) but it also said it can be run at 0 degrees with no problems. I have the keys so i can quickly switch them out but if it is not going to be a problem then i won't worry about it.

I figured someone would know here. I wanted to be sure before i went any further.

thanks in advance.
justin