If you are going to do that, take the Mikarb jets with you, so that they can match up the new ones of the same type.
There are a variety of Mikuni jet types, and you need to get the right ones.
If you have to get a needle jet, that is not a Mikuni part, and you'll need to order that one.
Hopefully, you won't need one of those, but we can't tell until you do further testing of the jetting and screw settings..