Tips for keeping small mothers - soil or coco etc ?

[Kevuk]

Would 4 x 10W IKEA vaxer bulbs keep a couple of bonsai mothers slow growing and happy?

Im following oldtimer1’s guide to bonsai mothers but I’m wondering if traditional bonsai pots would be better for root trimming?

I use coco, but it seems soil is better for slow growing mother plants, so I’ll give that a try.