Talking trout & me here...
Tippet size is more related to fly size than stealth. I fish a lot of small stuff, down to a size 32 on occasion so I also fish tippet down to 8X.
I only use fluorocarbon because it sinks, stretches less, it's denser so it casts better, twists less, has better abrasion resistance and especially because it doesn't flat spot like mono. Currently, I only use JDM Seaguar Gran Max or Orvis Mirage.
In my experience, I can get by with less than perfect drifts with a more supple tippet so when I am making repeated casts to repeated picky risers (like when Trico fishing), I'll always fish a lighter tippet like 7X or IF I think it will make a difference, 8X.
I especially like light tippets when fishing terrestrials because I can get a better splat. It is VERY common for me to fish 7X when using a size 16 foam beetle, bee or inchworm. MANY times at many places using the same fly without moving an inch or casting to different fish, just going to a smaller/lighter tipper of the same length made the difference.
For most of my non-blue line dry fly fishing using the size flies I fish most often, I am using 6X and at places with weeds or a lot of obstructions like the Letort, 5X. Blue lining on top is most often done with 4X or 5X.
Sub surface anywhere; 3X or 4X when deep dredging and lighter on small droppers when it may be 5X and as light as 7X on midge pupa.
The fear factors some folks have with light tippets are exacerbated by unfamiliarity and seeing low stated breaking strengths. IF you ever think you will need or want to fish 7X or 8X, do yourself a favor and add it to your leader, tie it to a tree branch and with the rod you will be using, pull until it breaks...
I think you will be shocked just how strong 1.5 to 2 lb test really is...
As far as twisting with light tippet goes, fly construction & proportions, line speed, tippet length and the number of false casts causes more problems versus just using a light SIZED tippet. As an experiment, knot a hackle tipped or quill wing dry fly with a nice "V" shaped wing profile to a long tippet, make a bunch of fast false casts and you will probably end up with macramé at the end of your leader.
Afterwards switch out to some other fly with a single poly post wing and/or no stiff parts sticking out; shorten your tippet, SLOW down on the line speed, CUT DOWN on the number of false casts (IMHO, most folks make WAY too many) and I think you'll end up with way less or no twisting, even when using 7X.
True story, I was fishing a bee pattern modeled after the picture on a package of Bill Skilton foam bee bodies (miss your foam Bill 😉). This was essentially a length of appropriately colored cylindrical foam lashed in the center of a hook with a few turns of hackle for legs, sort of like a big McMurray ant.
I was using some at Clarks Creek on a 7X tippet, but unless I slowed down my line speed DRAMATICALLY, my leader was twisting like crazy. When I got home, I made a revised version by lashing down the foam cylinder at the back & front of tthe hook so it had two sections like the original, but they didn't stick out from the hook in a "V" shape.
They next time I tried them. NO more twisting, even on 7X.
Overall, it helps me that none of my trout rods are fast or remotely close to fast. That helps keeps the line speed down and also cushion lighter tippets.
As far as the fish go, because I KNOW the strength of my light tippet material and don't take fish pictures or use a net; I horse in my fish and when they are to hand, I slip them off the hook while they are still in the water and off they go in a second or two...
One final note in regards to tippet/leader color...
I'm not talking fly fishing, but for visibility reasons on spinning reels and BFS casting reels I use for trout, I am currently using fishing line that is bright (almost florescent) orange or bright green. On a spinning reel I use for warmwater fishing my current line of choice is pink. On my micro fishing rods I use black line. On ALL rigs the colored line is tied directly to the lure or hook.
In every situation I have noticed ZERO difference in the amount of fish I am catching after switching from clear lines to colored lines...
Go figure...