I have rebuilt many sets of these for myself and others, and could probably help you. I have an ultrasonic cleaning vat and access to the proper size metric O-rings for the main jets, float seats, fuel transfer tubes and bowls. Often you don't need to purchase the carb kits, just replace the rubber bits. My price is negotiable and would depend on how deeply I might have to raid the spare parts bin, but would certainly be much less than any commercial shop.
Kevin