Hey Glort,
Just to expand a little on 38Ac's remarks - Gib Keys - Certainly can reuse them, preferably mark them and keep them with the wheel they were used on originally.
Balancing - The effort to lug them to a balancing machine alone, far outweighs the effort to do the static balance as noted before... Also, as said previously, those with built in weights on the rim can be dynamically balanced as a set, but would still need to do a static balance on each to get the counterweights to CG in the correct orientation. You would need to explain to the operator that they would be "wide spaced" when run. He would have to add weights to the rim in question to do the trimming. This "trimming" would only be for the wheel which would be lighter in the CBW department, easy to get confused, as both you and he would be new at it - completely different to regular wheel balancing. On the other hand, if he has a really sophisticated machine, he might be able to do a specific imbalance setup on both wheels individually, thus matching them as a set. Both methods could work really well, or really badly, depending on the skill of the operator, and the operator understanding what your needs are. In doing the CG setup, you are 99.9% of the way there, the remainder would be a small task... While you are at it, why don't you measure the CBW mass (with the bucket/string/stones method) and keep it on record for each wheel? would be handy to know when/if you decide to change RPM...
Once you pull the wheels, the rest is child's play. Pulling them a second time is even easier (Provided you don't use the "India fitment method".... To give you a general idea of the average "sweat" ratio when pulling a wheel:
Pulling Gib Key first time - 75%
Freeing wheel from crankshaft - 10%
Looking for tools, making puller, balancing, reinstalling - 15%
Lol....
Keep it spinning,
Regds
Ed