I see you are in FL, which right now would be high in temp and humidity. We also have high humidity here in NC. I have had great tunability out of the Odonell 97T plug, I think it's better than P4. It holds and amazing idle and also immediately comes down to idle if the LSN is tuned correctly. Taking out .4 of shimming will make it tune quite different, which is probably where you got lost.

Run the engine with the stock head shims first, which like I said is 2 shims, each being .30 and .25 mm.

My needle setting are roughly 2 3/4 turns out on the LSN and 2 turns out on the HSN. Keep in mind the HSN on the engine is really sensitive, so 1 hr. makes a big difference. SET THE IDLE GAP FIRST when using these settings. I set my idle gap by eyeballing the gap to half the distance of a 1.5 allen wrench tip, which puts you around .7-.8 mm gap. With an idle gap of this size, there's no reason it won't idle, so if you get a finicky idle, your LSN isn't tuned properly.

There's really no way around it, but in the summer with high humidity, the engine will run between 260-270 for good performance.