The one thing you need to be in the film industry is common sense, part of common sense is to recognize which relationships are worth cultivating and which relationships are just exploiting you. Its an important skill if you want to move up the ranks as a PA. If you work with the wrong people there are no ranks to move up, and you might end up jaded.
this is kinda bullsh*t, please new people to grip and electric find a better source to learn about lighting and diffusion. Shower curtains will work great for diffusing the sun but bad for small fixtures, its similar to opal or hampshire or have soft frost.
get a job as a PA, you'll get the experience your looking for
Balance your camera to the overheads, balance you lights to the overheads with plus minus green and ctb or cto if needed, figure out the style of your film and determine the brightnrss of your backgrounds and see if skirting the overheads is Needed, if so by masking tape and vid queen from Home Depot, where ever the talent is still, turn off the lights that are keying them from the overheads and replace the key with you lights in the right position for your look ad negative if needed for the style.
Shoot a MOS, then shoot another, and another until they are actually entertaining without dialogue.
I don't understand, why do you care about the very best, when you already realize the tools you want are flawed. If you are as run and gun as you imply, it really doesn't matter. If you don't have time or a camera that change nd filters, then the current clients won't care if there are issues. Just realize that there will be better clients down the road and builds gear for people who can tell.