splitting power between multiple wires

lets say i've determined the required awg of wire to be 16 awg for a circuit. when looking at chart i have on hand for spec55(0111A-x-x) wire i see that 16 awg wire has a diameter of 1.31 mm^2. for the ease of being able to pass the power through the same bulkhead connector i use for the rest of the engine requirements, (16 awg being too large for the contacts that fit) could i not use two 20awg wire that have the diameter of 0.518mm^2 each equating to 1.036mm^2 i know its less than the diameter of 16 awg wire but its also more than 18awg (0.823mm^2). or should i combine three 20awg wires together? i guess what i am asking here is when a large power supply is required for items such as ign1a coils( i know duty cycle becomes a factor here) pumps and fans whats the general rule here for breaking down the larger wire into multiple smaller wires to carry the same load that would of typically carried by one larger wire?

Yes, this is common practice. Make sure your thinner wires have at least the load carrying capacity needed.