I've read through this again, and I am a bit unsure as to how I should proceed. If I use the plastic connectors, I won't be soldering this, correct? It's a matter of getting the for connectors lined up (staggered or else it'll be too bunch up), but apply the shrink wrap overtop? Or am I getting this wrong? The other option is to solder, then shrink wrap (which is what a friend of mine did for me in the past) but then it is not waterproofed, correct?
Are these the connectors? https://www.princessauto.com/en/25-pc-window-butt-connectors/product/PA1000000709