For me it tends to be a single spring GEC 77. It's both as long and heavy as I can go before I notice it. The double spring 77 becomes thick enough that I can feel it in there chinos I wear to work.
In jeans I can do a Fremont Jack or other 79 single spring without noticing.
I do notice that in dress pants: keeping the knife upright is really important because once the knife goes sideways I can feel even a small knife like a Northwoods Norfolk. I sometimes carry knives in chinos in this leather keeper that stays in the pocket but keeps the knife upright: