Ugh, just looked, the same problem... they don't have a height option. The shirts are too short for my torso (and gut), and the pants are too tight in the thighs :(
The long john style liners are, well, long johns. They're stretchy, so they adapt well to body shape. The leg liners aren't cut particularly long--they have stirrups. You could choose to ignore or remove the stirrups and flip up the leg cuffs to make them a few inches shorter and they'd still work under boots. I haven't tried the shirt but it's the same material. My guess is if you match with the size you'd wear in standard long underwear it'd be fine.
The other respondent to me was correct, though--like all long johns these are fairly warm. I'm fine in them spring, fall and winter, but summer is a different story. It is an uninsulated open-weave mesh, so breathes well enough and it does a great job of creating air channels under your jeans, but I tend to just take my chances for a couple of months of the year rather than add more layers.
Edit: to make sure we're looking at the same thing, I mean the ones reviewed here, https://www.webbikeworld.com/draggin-liners-review/
I'll take a look again tho. I live in seattle where it's pretty cool most of the time.
It'd be great if new materials could be used to make protective wear that is thinner and more air permeable.
I wear them under regular jeans for casual riding (I always wear an armored jacket so no need to wear the upper liner) and would trust them in a low-to-freeway speed getoff about as much as any other mesh gear. You can stuff d3o armor into them pretty easily too.
It's not precisely what you're trying to achieve, but it's more versatile and generally looks better than full-coverage (Hood, etc.) riding jeans.