ShashChess 35 - What are the best settings?

[Magnum]

What are the best settings if I want to use:
LC0 + Stockfish Dev.
+ ShashChess 35 with only 1 core (or how many cores would you prefer and why?)
https://github.com/amchess/ShashChess/releases

If I have 8 cores and ShashChess settings are:
MCTSThreads = 1
Threads = 8
Does this mean it uses 9 cores total or is it: 1 + 7 cores = 8 total?

Is it still possible to make ShashChess better for analysis in terms of finding key moves and much faster checkmates, which Stockfish and LC0 can't find?

For the most precise +-0.01 evaluation, I'm using Stockfish, so it doesn't matter for me if ShashChess is much weaker at this point.