Most comfortable guitar body type for playing sitting down

[Gitfiddler]

I find thinline (semi-hollow or archtop) guitars most comfortable for my body type (tall, lanky and long arms).

That said, what is even more comfortable is a guitar with a rounded back rim. Strats have that feature, but they are thin bodied gits. I have a couple of Teles (G&L ASAT and Fender Kotzen) with a rounded back rims that suit me perfectly. Sitting or standing, they just feel great. Once strapped on, they're hard to put down.
Overall, I'm not picky and can quickly adjust to most any body style from a tiny-ish LP Junior all the way up to a full sized archtop.

[Gregc57]

For the sofa? My Larrivée parlor with 24” scale length. Perfect for quick noodling or working something out. Comfy on the couch, for sure.

[Sleeko]

I have to say, my L4 CES is the most comfortable out of all my guitars. The narrow waist and deep body let it perch in my lap just right. The only guitar I get a bit of a cramp in the upper arm from is my Elitist Byrdland. The shallow body at the lower bout cuts in a bit.

[JazzDaddyD]

To me the biggest issue with thin guitars is my right hand position- with an archtop I have a nice RH wrist position, with a thin guitar my wrist is flat or concave. When you play bebop at 280 bpm it makes a big difference! That's a joke, folks-

[pdfiddler]

335 types =best
LP types=worst

[RJVB]

I suspect my resonator would be the most comfortable to play sitting down on - it's a bit small but it's probably the sturdiest of the lot and might just carry my weight

I play in classical position and use a support (De Oro) instead of a footstool. My Loar is probably the most comfortable match to my upper body but it does give my right leg a bit less options and it'd be easier on the left arm if it had a 12-fret neck join. My Cabaret and resonator are both a bit too small (or the supports too low) but the comfort of nylon strings (and wider string spacing on the Cabaret) make up for that.

All in all they're all compromises and I usually don't need to remind myself I have to change position or get up regularly with any of them.