More light first, then cut. The probability of success if you cut right now (given the way the plants look) is close to zero. You might try a leaf propagation instead. Otherwise dial up the light and wait until spring before taking action. Spring is generally a better time for this sort of thing anyway, with the stronger light and warmer temps it brings.
I cannot advise much on artificial light as I have no experience with that, but the distance from the light to the plant is very important (shorter is better, up to a point) and the light should generally be annoying and uncomfortable for humans to be around in order for the plants to reap the greatest benefit. See here for more:
The thread "Artificial light for cacti and other succulents" in
Cactus and Succulents forum
