I think i may be able to help you out here.

Too much heat does pull a gunky product, as you have already learned. The remedy here is to add your lye solution slowly in small increments while stirring so the basic soup does not get hot too rapidly. 10-20ml every 10min works well for me.

Allow time for your jar to cool before adding solvent, heat bath the whole container until the glass feels warm to the touch. I like mine just as the point the bottom of the container starts to give that bite to the hand from heat. It is still not too hot to handle with ungloved hands at that point.

The clear film is always there for me. Or at least i have not been able to extract without it occuring yet. It seems usually to be very active, but using less heat along with precip in a pyrex dish vs a mason jar seems to minimize how much there is per pull. When using a baking dish for precip it allows you room to easily scrape the crystals from the clear gel without picking any up if you are delicate when scraping the crystal.

The gel/goo i am working on figuring out if is somthing that is normal or it happens from something i do during extraction. It seems that without it the crystal formations may not even stick to the tray. What i am doing is after scraping all the crystal i can, dissolving the remnants in my dish in vinegar & using that to wash solvent after pulls & then later collecting a the vinegar wash & using that to extract from to recover more DMT. I want to try & see if all that clear gel maybe forms actual crystals if the precipitation process is slowed down. 24hr room temp precip, followed by 24hr fridge precip &  24hr freeze. I believe it to be mostly DMT based on potency, it seems like maybe it just precips so quickly in sudden temperature change that it traps impurities & does not get the oppertunity to form a good crystal lattice, obviously it being under rather than on the crystals, the gel has precipped first.