Hey @ Leviathan74
Nice post.
1) The field generally is getting more competitive, so it does make sense you are finding moderate competition within the pool. Pre flop ranges are incredibly important, a solid foundation is a must to do well in this format. You need to ensure you are going post with the correct hands, in relation to the stack depth, position and opposition. This will come in time, there is various tools out there such as Holdem resources calculator which can help.
2) HUD interpretation is important vs regular, but a decent sample is also needed. You do not want to over adjust vs small sample sizes as it could easily be card distribution variance etc. Have some weight on the stats before you try to interpret. For me, i would argue this is not as important as point 1 you raised to start. Focus your attention there.
3) WTF plays exist at all stakes, whilst they look random, sometimes they could be a solver play. ( Not so likely at the 5s tbf, it could just be total randomness) You have to remember its a game played by humans and therefore emotional factors could also come in to play. You can note these plays, but once again, carefull how much weight you put towards these.
4) It does not make sense to grind for rakeback at the $5 level. You would be alot better reducing your tables and becoming better at the format. You will earn alot more money increasing your CEV, than you will by increasing your rakeback earnings.
The most important thing in Spins is the fundamentals, Pre flop ranges, post flop tendancies such as board structures to CBET, how to change your style vs different opponents, how to understand weighted HUD stats etc, all these things are really difficult to improve on if you are playing too many tables. 1-2 tables is completely fine in the early days whilst your honing your skills, any more than this and you are likely leaving CEV on the table with every spin you play.
Good luck with your journey and keep us posted