Some work to a rule of big + big not through RD + 2 links, others wing it.
I winged it last week and it worked. Fit the chain with the quick link though the mech and see what it’s like. In big cog at back the mech cage wants to be pretty stretched forward but not to the point where it’s horizontal. In the small cog there needs to be a bit of tension left in the chain, ie it needs to be pulling on the mech cage slightly and the chain doesnt want to be loose at all.
If running on a full suss don’t forget to collapse the shock and see if that has any bearing on it and adjust accordingly. The beauty of a KMC chain is that you can fit it at full length with the link then just shorten it by two links at a time until its right