Upper end of temp ratings?

I'm looking into my 1st quilt purchase and am leaning toward a 3/4 quilt over a full but am having trouble deciding on the temp rating. I mostly hang in North Georgia and GSMNP in North Carolina in my WBBB. For the majority of the summer I didn't even need any bottom insulation but would like something to carry me through the rest of the year. If I got a 20* would I be too warm much of the time? What is the upper end of the temp rating on a 20* quilt (the point of being too hot)? It's kind of a big purchase but I am willing to drop the bucks on the right quilt. I just want to make sure I get the right one! One problem is I never take a thermometer in the backcountry so I'm not even sure of the temps I tend to hit throughout the year - something I didn't have to think about as much when packing ground gear. Any GA or NC peeps here to chime in? Also, this is my first year off the ground and this will be my first winter in my hammock...I freakin' love it and am quite addicted!

Temperature ratings are hugely personal. At the CO Fall Hang, my wife was in a 0° bag inside another 45° bag and she was JUST warm. I was in only the 45° bag and was too warm. That's at 11°.

The nice thing about underquilts is they can be vented. Go colder than you think you'll need, and you can always vent it for warmer weather.

I also live in Georgia and just went through the same thing. I went with a 20 3/4. I would rather vent and have more verstitlity to camp in colder weather. Also at 60degrees I'm good with just a tq and I don't think I'll have issues venting at -60. My two cents.

my personal summer UQ works down to 40, or less. vent the ends on a rectangular quilt (NOT tapered, like some) to let a bit of air in.

good thing is, heat rises. i've used a 20 degree quilt in 60 degrees with no overheating.

What do you sleep on at home? My mattress is 10" thick. That's a LOT of insulation. Do you get hot on the bottom at home? At home you adjust the top. Same thing with a hammock.

In my opinion you can never have too much bottom insulation. The converse is not true, you never want to have too little insulation on a cold night. With a (DIY) down under quilt you are talking about a few ounces of difference between temperature ratings. The question is how much you want to pack. For me, I carry a heavier than the minimum required because a warm butt is very much worth it to me on a cold night.

It's sounding like a 20* 3/4 rectangle is the way to go. I wasn't factoring in the venting as such a versatile ability. So you guys think a properly vented 20* could serve me well up until I could go without insulation all together? Or is that a bit of a stretch?

There are places I am willing to shave weight - warmth is not one of them. Besides, with eliminating a sleeping pad, a lb or a little more or even less for an underquilt instead is a no brainer