Welcome @pompei. Enjoy your "modifying". Hope it goes well. In my limited experience I find it easier building from scratch than modifying or repairing other guitars but if you can master it can be an easier way to make some money......if that's what you're aiming for.
🎸🙂🎶🙏
🗝️ "Life's what you make it"🗝️
but I'm planning on "modifying" some old cheap guitars ...
Ahhh, that old first step on the slippery slope.
Before you know it, your Dining Room table has been re-purposed as a workbench, there are bits of wood lying just about everywhere, waiting "to come in handy one day" and a bathroom is now a finishing shop.
(It can't be just me ???)
Online guitar making courses – guitarmaking.co.uk