Check with the company you buy them from, they should be able to provide the carbs properly calibrated for your application so you don't have to disassemble them. Make sure to provide the details of your ski and engine size including year, and ask them specifically if the carbs will be correctly calibrated using the correct sized jets and pop-off setting. They should know those details and send you properly configured carbs, else you may have to disassemble them and swap out the jets, which defeats the entire purpose of buying new carbs.
There are only five external adjustments on a dual carb setup, the new carbs should come with full instructions on how to fine tune them. If not, obtain a copy of the BRP factory service manual for your ski, there are instructions for the factory settings in the carb section which are specific to your engine/ski combination. Basically, you need to make sure the low and high speed mixture screws are positioned correctly before installing the carbs, and once installed and running adjust the single screw for idle speed, target is 1500RPM in water or ~3000RPM out of water.