I used a long piece of hex ................... I also wrap the long piece of hex with electrical tape (in the right spot) as to protect that ....bushing .....
I simply don't agree that this is a good idea. WAY too easy to FU the bushing.
To the OP, you can drop the dist. gear in "last" after the manifold, etc is on. If you get it in wrong, you can "walk" it back up and out with a screwdriver, just turn it and the helix of the gears will force it back up and out.
In fact, if for some reason you cannot get it in correctly (a little new tightness, etc) you can just move the plug wires on hole if needed and time it