Yeah, honestly, see if your LBS has a QBP account. If they do, they have access to the QBP spoke calculator, which is usually spot on.

Otherwise, DT Swiss has a good online calc.

You're still going to need to measure everything by hand. I know with DT Swiss you can always round up or down depending, but with QPB's it tells you what you should go with regardless.

You can always do the measurements yourself and then take them to your LBS and have them double check it for you.

Beer works for a good bribe (only because I work at a shop and like beer).