Straight from the bottle is preferred, even when airbrushing - I’ve heard that cutting it with anything will generally speed up the dry time, making it less likely to self-level. As far as the other airbrushing questions go I’m not sure as I almost always brush it on with a good wide brush (most of my builds have been 1/72 scale) The only thing I can tell you for sure, if it is pooling on you it’s being applied too heavily. Just like paint, you’re better off with a couple of light coats rather than a single heavy coat.
I know there is an IPMS Chapter somewhere in San Diego but not sure how convenient that is for you in IB. There is also a “cross border” modelers club in your area that is out of TJ/San Diego area. Those guys are great! They come up here to the local AMPS chapter in Orange County on occasion.
I usually spray my Future from a distance of about 12" or so from the model…very quick/light passes, and I also paint with MM enamels as my preferred medium. The key is multiple quick light passes and pauses in between the passes so that it has a chance to dry a bit and not “pool” like you would get in a single heavy/wet pass. The goal is to build up a fraction of a mm coating, not a thick hard shell, just enough to protect the underlying paint work.
No need to cut Future with anything, spray it straight from the bottle, and make sure you’ve got a good amount of PSI as well…I typically will shoot Future at about 25 psi and use an Aztek airbrush fitted with a wide bore nozzle (the orange tip) to help get a nice mist “flare” at the desired distance. If you’re shooting the Future through a narrower tip/nozzle, you will need more distance between the airbrush and model to get that “mist” effect.