I am in the fortunate position that I was able to borrow one. Once you have obtained one, the only advice I would give is to have an enthusiastic assistant of similar or greater weight and strength to you. Establishing the compression ratio for the fork and the shock is hard work and it's tricky to read the instructions whilst also pumping away on the bike. Once you have that, set up is a doddle. When the ShockWiz tells you what the compression ratio is, WRITE IT DOWN. Once you have done the fork and shock, you may wish to redo them again. If you know the compression ratio, as I said above, set up is a doddle.
Also, make sure that you have some spare CR2032 batteries available. The ShockWiz I borrowed went through them quickly. You don't want to be paying expensive rental on the ShockWiz while you hunt around for cheap batteries.