Well, some do it without the dynojet kit too but it's part of a dynojet kit.
Nightrider has a good write up on tuning the cv carb on evos and TCs. He also says to drill the slide out. But if you're using the N65 needle, then he also says to use a 165 main rather than a stock 180 in my case. Probably a 170 in the OP's.
My dynojet kit had a 45 slow/170 main. 42/180 is stock
Basically they up the slow and downsize the main for smoother transition on both ends of the mid (the needle).
that's my conclusion anyway.

I had thought about toying with the drilled slide and upping the slow and downsizing the main like Nightrider says to do with the sportster needle to test this method but I like the way it is now way too much and I just don't want to mess with it.

 

Don't drill the slide...YD

 

I have proven to myself, on a dyno, that the CV carb performs best with OEM parts. I have compared two kits, Yost and Dynojet, against an SE44mm carb on an all bore 107" motor. The difference is not major but using OEM parts in the CV carb consistently made a bit more TQ/HP on the dyno than with either kits and also deliver better fuel economy.

I don't see any issue with drilling the vacuum part and installing a lighter spring. The CV is vacuum operated and both those modifications will provide slightly quicker throttle response; minimizing lag between twisting the throttle and feeling the response. The Mikuni guys "feel" that the Mikuni makes more power but really what they are feeling is the quicker response from the cable operated throttle/slide. I have seen, and can post if anyone is interested, direct comparison between the CV and a comparable Mikuni and the difference is marginal and certainly not worth the expense to replace a CV with a Mikuni.

There is no set formula and every motor is different; just gotta give the motor what it wants.