Thanks again to everyone that replied to these questions, super helpful for me (and hopefully others too)! 
So thought I’d do a summary in case anyone is interested…
Question 1 - Do you tune to the attack or decay of the string?
Votes for attack… 4
Votes for decay/release/sustain… 2
So attack takes the win 
Some great points on both sides and a really interesting debate so I still feel a little unsure although leaning towards attack based on my playing. In saying that, having the Evertune setup, I can adopt Kasper’s method and avoid the problem altogether, so… yay! 
Regarding intonation, this seems to be a specific issue with my newer Solar based on its setup being done incorrectly (by myself of course! 
). Again as Kasper suggested, I think the action is too high and relief needs adjusting as well, so I will tackle this in the weekend when I have more time to suss it out. As a side note, I restrung my original Solar last night (the GC1.6 Flame Amber Burst) and have it intonated perfectly right up the neck so that makes me more confident about the other having a setup problem.
Thanks again! SUPER appreciate everyone’s input 
(PS not necessarily end of thread if anyone else would like to add to the debate 
)
EDIT: Sorry meant to ask!! Does anyone know what Justin does regarding tuning to either attack or decay? 