BB
Being lean is not a curse. It means your size does not sell out as fast.
Until I aged it worked very well for me. At your age I was 6'2", 135 lbs, waist 28, hips 31, length 25. Trousers were size 28 and very loose. i had no problem finding for the lower part. I have a looong torso, shirts very rarely got anywheres near my trousers. The kilt is worn high enough to overcome that issue.