I hit it left, right, upside down, underwater (okay maybe not), point being, doesn't really matter. Never noticed a difference. Hot air rises, that's about all I can say about hitting it upright .. But .. Good thing our lungs can manipulate the physical properties of gasses and air
You'll slowly learn the line of where "cashing a bowl" is. I used to like to push it dark (I can get it black no problem 90% of the time it I wanted too), but I've been getting such good results from it that I rarely find the need once the flavor is gone.
I can tell you this for sure. Back to back hits is much easier to cash a load than waiting for 10 mins or so, just way way more consistent.
Despite your hot unit, you're doing great man!
I get over 4 bowls a battery without any concern. You'll get there, and if you can't, maybe contact rbt, just use the residual heat more. Really , once the vape is up to temp, you can let go of the throttle and just ride it out with a slow inhale for about 7 seconds. The throttle is just to get to temp, not necessarily to fully achieve a hit all the way through. The heater holds heat quite nicely even when not active.
Glad to hear of the improvements man! Keep it up and keep us updated!