If you are talking about the S-mesh statics, I primarily use them now for both plastisol and discharge and I am a manual only printer.
I keep my off-contact at about 1/8 of an inch for everything, which is maybe a touch low for some plastisol work and a touch high for some waterbased, but a good balance for both. I hate having to adjust it honestly...
I use 180S for my white plastisol base on spot jobs, and 225S for my white plastisol base on process/sim process work, or basically anything with tonal underbases or fades. I use 55LPI for everything these days and the 225S holds that well. For discharge underbases I use 225S almost exclusively, though I have done a few with 300S when printing more colors due to the viscosity of the clear discharge base and having it sort of come through the mesh and blur detail when it sits longer between print strokes. In other words, if I have a discharge base, then print 5 top colors, it may not get printed again for a minute or so, which can cause issues as ink starts to "drip" through the screen due to gravity.
For a simple p/f/p plastisol white I almost always use 225S now.
For standard discharge only prints I have been using 180S for white and 225S for colors. I occasionally use 300S for black halftone photo type waterbased prints.
I have played around with 135S for one hit whites using a 2/2 coat and it ALMOST works well enough, but I still prefer the p/f/p 225S coated 2/1 currently. I know Alan has played around a lot with the lower S meshes like the 90S and he seems to like that for his white spot one hits, though he is using rollers and an auto.
I guess for me I found that the 135S and 150S were too open for p/f/p but not open enough for one hit whites, so I really don't use them at all anymore unless I am out of a better mesh and need to get a job out the door. I find that 180S offers that little extra over the 225S for clean spot bases and discharge white spot jobs, and the 225S is really my workhorse screen right now. The 300S has it's place for a few things as well.
I REALLY wish they made like a 270S specifically for plastisol top colors. I really like using 280 standard mesh for top colors on a 180S or 225S base, but it takes 2 strokes manually to clear many colors cleanly, where an S mesh would probably clear in a single stroke. The 225S lets through a bit too much ink on certain runny colors and can cause tiny issues with blurring and pickup on screens.
edit: forgot to mention squeegee preferences. I have some of the metal ergo squeegees and have started to prefer classic wooden squeegees more. The metal ones are less comfortable to my hands on long runs for whatever reason. Mostly it has to do with where my thumbs rub.
I prefer using triple durometer squeegees for basically everything, and use only triple durometer for white ink (plastisol and discharge), but standard yellow 70 durometer works fine with everything else and I still mostly have those in my shop.
I round all of my squeegee corners. I found that it makes discharge screens last longer and leaves a less noticeable pressure line on shirts where a lot of force is being used, like on fuzzy blends where I double stroke the base to get it nice and smooth.