I've never heard the vacuum advance canister called a vacuum head before.

It may be easier to switch the wires around but it will be a problem for the next bloke trying to fix under the hood.

I used to worry about lining things up. But when I saw how easy it could be done, it makes no sense to move the wires around. The key is that the intermediate gear can be turned quite easily in the backwards condition with a flat bladed screwdriver. So with #1 piston at TDC on the top of the power stroke, turn the intermediate gear until the slot is pointing in the right direction.
Then install the distributor with vacuum advance canister pointing in the right direction and the rotor pointing at the #1 spark tower. This should be quite close. Then rotate the engine two complete revolutions and stop about 10-15 degrees ahead of TDC. Line up the pickup and the nearest tooth on the reluctor and tighten everything else. Put in the wires according to the diagrams and you're home free.

The key really is moving the intermediate gear by rotating it backwards.

R.