May I suggest, not touching the roots at all, in fact do not bother the plant as much as possible. Get a bigger pot, then transpot the whole plant to the new pot (without disturbing the root as much as possible) then just add more potting mix around to fill. This way hopefully your plant will have more room for roots to grow.
Please do consider the technique that has worked 100% for me so far to get basals, and that is to make position the vine horizontally or even lower than the pot. If basals is what you are hoping for
Good luck!
TTFN
Arvin