Who uses all the power setting on there gun and why/how?

I understand there is a need for some people to have different power setting. But I don't find my self using the low setting at all. I have wonder what type of regular use's people have with the lower settings. I can create the hypothetical, I was hopping for real world experiences. I like knowing we're my zero's with the in and out's of my shot. Maybe I should have all the power levels maped out? Maybe some of us have some great experiences they like to share. 
 
I did this with my Royale 400 .177. I mainly shoot it on the middle power level. But I have range cards set up for all three power levels. On setting one I use 8.4 grn pellets for plinking in the backyard or taking the occasional sparrow. I use setting 2 with 10.65 grn pellets if I want to stretch this out a bit further. The same for setting 3.......a bit further reach and flat trajectory. Just keep in mind, at least in my case, the same pellet did not perform well on all settings. You'll have to find the right pellet for that particular purpose. So no matter at what setting I decide to shoot, I simply re-zero and I know where all of my shots will land. 

Keith.
 
I have a Royale 200 and use the high setting for longer range target shooting with JSB18.13 pellets and for 25m bench rest shooting with the Air Arms 15.89 pellets. I use the medium setting for field target style shooting with the JSB 13.34, which keeps it under the 20 foot pound limit. I keep the zero from the high setting and use the mil dots to hold over and have a range card of sorts for varying distances. I use the low setting to work on my trigger control for the 25m bench rest shooting and to plink around the yard.

Here's an advantage to the power wheel that I haven't heard anyone talk about and that I'm going to have done on my Royale 500. I'm going to have the gun tuned to shoot the JSB Heavies to an optimal velocity (850 - 860 fps or so). Then I'm going to have the lower power level (only 2 power levels on the 500 as compared to 3 on the 400 and 200) transfer port (or whatever that hole in the power wheel is called) bored out so that it shoots the regular kings at around 880-890 fps. This way I have the long range advantage of the heavy 33.9 gr pellets and, if I want to shoot shorter distances or just plink, I still have the 80-85 shots per fill that I get from the regular kings (rifle is regulated). All in one gun with only needing to turn the power wheel. Think of the possibilities of doing this with the power wheel on the 200, 300 and 400 models that have three settings!!
 
I have a Wildcat .22 and it has a hammer spring preload adjustment screw, and if I back it off, I get way more shots per fill, (hand pumper problems) and screwing it in, the hammer hits the valve harder which makes a rather noisy and wasteful burst of air but increases the muzzle velocity quite a bit which is nice for longer shots. 140+ yards.

What I would like to try is bumping up the regulated pressure and backing off the hammer spring preload. Theory being less air volume per shot at a higher pressure to achieve the same muzzle velocity. The trade off being the usable regulated pressure range would be narrower. 
 
Rarely used e on a career 707II .25 in Winter for indoor shooting , it had the rotating valve stem travel limiter style set up and shot 39g from 0fps to 999fps. I did know to start 6 clicks from highest for the longest string, then 2 added clicks after 6 shots ,..... Didn't use it that wat much though, 999fps avg for six hunting shots ( Chicken eatin vermin )was it's real job. Has a BUNCH of similar old Korean riflkes and just shot all pretty much on high.
I tried one .177 ( and don't recall the model) that That was a disc with transfer port holes in it type. It shot right at 6fpe, 11.8fpe and 19.9fpe I liked it so say Barn work at 6fpe and squirrel , rabbit , target work & field Target at "12" & "20" fpe.

Have an older AA410 .177 that has a "power tune" ( drilled for an Allen screw TP restrictor ) at PAG just to get it under 20fpe, it came shooting a full 23fpe , in .177! It has been set once and never toughed again. Used for field target and hunting and fun.

HATE the totally variable and non repeatable transfer port knob type! Worse than useless for me.
IF a rig has a factory power adjustment ( external ) it MUST be resettable to whatever given power so a chart can be made or better yet it repeats so close you'll just remember the holdover/clicks.
IF the adjuster just allows adjustment ( like well all used to do with DIY home care, springs, ports, ... ) and you've no idea where you are now shooting without a chrony workout, it would be a desired feature for me.

I like regulators and a set power level most.

John