I’m properly useless with things like this but gave it a go on my last 2 buys.
First one I bought a cheaper hardtail kit (was still about £30) and rushed it and it was crap, took half of it off and it got mucky on the edges straight away.
Second time on full suss I bought the invisiframe kit and I spared a week to do it, just did a few pieces each night for an hour or so each night and was much better and less stressful! The invisiframe kit was also much easier to fit and the edges don’t gather muck, or what does gather just washes off.
I’d get the proper kit again and just take loads of time with plenty breaks, using loads of water too incase your need to move it before you squeezed it too much.
Although I’d probably just not bother unless it was for a frame that I want to keep/ been a big investment to me personally.