Find the initial timing point where the engine kicks back when hot on the starter or where idle vacuum is greatest at a constant rpm, whichever is lower. Kick back minus 2* or highest vacuum/back of timing so 1" drop.

Set the rest of the timing events using the above as your foundation. It's an exercise in finding the efficiency point of the engine at idle.

Setting mechanical advance is easy if the MP distributor has a mallory advance system in it. Use drill bits to set air gaps. No need for the keys. Old style requires welding or jb weld in the slots.

Simple test at idle, twist your distributor a little clockwise, if it picks up rpm, it wants the timing.