Based on my 3 pks experience.
I just use an all rounder. Vittoria XG Pro. Didn’t change it for the race. I bumped mine up to 70PSi and I’m also 80kg riding weight.
I normally race as low as I can so 20-40psi depending on the course.
In summary, leave em on and pump them to the max.
If you do want new tyres then you want something more slick. I’d go for a profile tread over the land cruisers. There is a lot of road on your ride compared to the three peaks and I doubt they’ll have decents as bad, more likely to be gravel than full on rocky. Again 60+ PSI will give you a faster ride.
I’ve had good results riding rocky long rides on conti CX speeds at 60-70PSI but only if it is dry and there is no mud.