OK, let's get this over with

If you DON'T pull the distributor out:
The wires will have to stay virtually in the same position regarding the engine, because the rotor isn't moved either. So only the dizzy needs to be turned. If the vac can is hitting the intake you won't be able to turn the dizzy CCW, only CW will go at all. Turning the dizzy CW will retard your timing by twice the degrees you turn the dizzy because the rotor in the cap only turns once in two engine turns. If you're now on exactly 0 degrees and want to be 8 degrees advanced you'll have to turn the dizzy an eighth of a turn CW minus 4 degrees, making it 41 degrees of turning the dizzy. Then all cables should go one terminal CCW. Like this you have changed the position of the vac can by 41 degrees, which should get it away from the intake, but the position of the cables has only changed by four degrees, cable length shouldn't be an issue then.

If you DO pull the dizzy:
Distributors are a bit fiddly to get back in, because the oil-pump drive shaft needs to lign up with the end of the distributor drive shaft AND the cogs on dizzy and cam need to mesh. You see at once that you've got it wrong if the dizzy flange stands out about an eighth inch above the intake. When the dizzy is out you'll have to take a long screwdriver and turn the oil-pump drive shaft by a couple of degrees CW, not by much. Then you have to wobble the dizzy back in, dizzy AND rotor will now be at a different position regarding the engine, so you wont need to rewire. Doing it this way is more of a mess and takes longer but can be the cure of too short wires with some wire-sets or if you're using looms because you can change the position of the wires regarding the engine, which you can't if you don't pull the dizzy.

I hope I got this one right. No doubt I'll be corrected if I'm wrong...