I'll share my technique, I'll make no claims that it's "correct"
I use a stock Ozone Foil Race control system with lots of depower.
For the power stroke, I usually trim in about 2-3" so the kite doesn't stall, then as I'm up and riding and accelerating I'll trim in another 6-8" so that I have 15-20% trim remaining. I only ever fully trim when I'm super over powered in somewhat survival mode.
My goal when going upwind is to accelerate, get my board/body in the right position, then pull in the trimmer until the bar is in a comfortable position with my arms. I have a low-back injury, so I can't do the full poo-stance anymore, so I get where I feel balanced with my chest out/shoulders back, and then trim so that my arms aren't reaching and that I can comfortably sheet the bar out in a puff or if I get overpowered. If you're on the right kite, you should be able to sail with a pretty stable body position and just move your arms in and out 3-4" to control gusts.
One thing to note, you're not trimming the kite to feel more bar pressure, you're trimming to go faster. Sometimes, you can let the trimmer out and feel a lot more line tension, but that's not necessarily power, it's actually probably just a bunch of drag. You want to pull enough trim that when you're riding you can sheet in and prevent yourself from falling backwards, but when you sheet out a bit the kite flies forward in the wind window and accelerates.
I'll describe the bear-away at a windward mark of a race. You approach the mark, usually on Starboard tack, and right as you're rounding it and starting to head downwind, pop the trimmer ALL the way off (which in my case causes backstall) and the kite should fall WAY back in the window and pull like a friggin truck. Use this pull to 'slingshot' yourself around the mark, then pull on about 1-2" of trim (or however you have your bar tuned) so that riding with the bar at or near the chicken loop is full power (not backstall, as is the case with my bar when the trimmer is all the way out). If the kite feels slow, backstally, or draggy pull about 2" of trim. If the kite feels like it's too far forward in the WW and you can't head deep enough downwind to be competitive, you can let the trimmer out and the kite will fall back in the WW more and get you deeper.
This is always a trade-off with speed, so what you're trying to do is go deep when the puffs hit and you're powered up, and edge upwind slightly to accelerate when the wind slacks and you feel like the kite isn't keeping up. Like was said before, you can go downwind a bit flatter to the water which will reduce drag, but if you're going properly fast, your apparent wind will shift forward and actually fake the kite out into feeling like it's sailing upwind; for this reason, ripping downwind is almost the same body posture as ripping upwind, although you're not trying to edge upwind incrementally you're doing the opposite, edging downwind when the gusts allow.