Welcome here!
Concerning carbs:
both types are available in 26mm, which, correctely jetted, seem to be enough for 150cc
-with a PWK carb you might have a little bit better performance
-a CVK carb is more reliable and has better fuel economy
There is no magic formula which is spoken over a carb and makes it work wonderousely.
Only road testing with different jets is a way to success.
Maybe watch this link...
https://www.kymcoforum.com/index.php?topic=31762.0About roller weights:
Again no easy way to find for YOU the right
a) weight
b) shape
c) performance
..as a start leave original rollers in your CVT and testride..with your carb of choice
You are not happy with your taking off from start
- try lighter rollers
You want a more quiet cruising,
- try heavier rollers or Dr.P gliders
Maybe watch this link for some inspiration..
https://www.kymcoforum.com/index.php?topic=30655.msg214654#msg214654