Without want to upset the old tradition of doing up your cart wheels with a bit of slack, modern bearing materials respond much better to having a little pre-load. The pre-load helps spread the forces across more rollers and extends the life of the bearing.

Caterham (when you talk to the right people) recommend 8 NM on a new bearing, however it should be less on a bearing that has run-in. I would apply 8 NM (and that's more than finger tight, but not a lot) as you rotate the wheel, if not aligned with a hole then back it off to the nearest one. No slack or play should be felt.