Ignition leads what ones??

Hi Team. I need a new ignition lead that goes from my coil to my distributor. I have an Early Bay 1971 with a 1776cc from The VW Engine Co (not a type 4) with a Pertronix electronic ignition. Im getting a bit confused as there are 7mm and 8mm that are for up to 1600cc. Can I get a view on what leads to order or doesn't it really matter? Also is there anywhere I can get just the lead from the coil to the dizzy I want and not the whole set? Cheers

Taylor 8mm spyro leads, cut to length so can be made nice & neat. Cool
Air sell them