Hi, I'm not really that into gel, myself, but it's generally much easier to file off than l&p. The gels I've trained in <Brisa and Ezflow's Gel It> are better suited to hand filing, but I'm not sure about your brand/s?
Whatever method you use, I think a lot of us struggle with rebalances etc and they can seem at least as much work, if not more, than a new set. I know that this has been the case for me. If you are happy with your new sets after only 3 months <well done!>, then I don't imagine you'd have too many problems with rebalances long term. I think I would persevere with practising your hand filing for this task, tbh. Good luck with your venture.