Cant speak specifically about the creedmoor but I do load for 260rem.
I would stick to the N150/N160 powders as the 5 series powders are higher energy I believe.
Not tried any of the elx type bullets due to the cost of them.
I am a fan of 123gn and 139gn lapua scenars.
Both shoot well to 1k plus.
And they are relatively cheap in 1k boxes and always available.