Stranded 8G Wire; Tinned?

I have a run of 8G stranded wire feeding power to my aux light control box in the engine compartment. I intend to cut into the wire and install a 1 IN 2 OUT splitter so I can feed a branch into the cabin. I intend to use the same 8G stranded wire. But... The splitter employs Allen screws to attach the wires to the little terminal block, and I always wonder when I crank those down: am I getting a good connection with the strands all splayed out flat inside?? In the past I have tinned the ends so that they are un-crushable, but I vaguely recall reading somewhere recently that solder wicking into the ends of stranded wire is a no-no. Is that true? Why? Now I should point out that I have carefully selected a splitter that is specifically for 8G wire; no one-size-fits-all here. Therefore I presume (hope) that - rather than a bushing inside a large-bore fitting -- it will in fact be the right I.D. for 8G wire. If so, I guess it will be alright, but I am still keen to hear some feedback, please & thank you. P.S.: I do not yet have the splitter in hand - it is on its way. If you wanna look, it's a Stinger [SPD510] P.P.S.: I also recently came across the term "potted" with regard to this same practice, but the term is unfamiliar to me. Is it just a different way of saying "tinned"? (i.e.: the act of dipping the bare end of a wire into a pot of molten solder?)

Ever thought of removing about 10mm of insulation, wrapping the end of the other wire around it, properly soldering then covering with adhesive lined heat shrink?

I hadn't, no. Partly because I have tried heat-shrink tape with very poor results...but also because my soldering skills are less than incredible. But your suggestion *does* indicate that soldering stranded wire is quite acceptable (which I had always believed)

Proper soldering, i.e. letting the solder flow freely into the joint makes a more conductive joining method, also heat shrink TUBING, not tape. I mentioned adhesive, more expensive but better under the hood, resists damp, corrosion better.

Forgive me if I sound naïve, but I can't figure out how there would NOT be a split in the tubing if I am introducing it onto a 'Y' junction. Of course I can slide a 2" piece along the new branch before I solder it...but I'll not be able to slide a piece onto the existing "feeder" wire; there is going to be a slit in it somewhere, isn't there? And wouldn't moisture get into the joint?

Remove the wire from the control box then slide the tube back from there.