Get tired of talking about soap? Oh, dear girl, you really don't know us at all!
Rendered tallow? Oh YES you can use it! Maybe 20% CO, 40% OO, 35% tallow and 5% Shea? Things like Crisco, sunflower oil and so on can all be used for soaping. Or maybe even 15% CO and 10% shea if you prefer?
Out of interest, how can you pour your soap higher than the mould? Can you picture pouring soup higher than the soup bowl?
As for controlling gel by preventing it, you can put the mould in the freezer just after you pour the soap (do it before you make soap if you really want to be safe), then after 12 or 24 hours move it to the fridge and then a cold place and keep an eye on when it is good to be cut. There are people on this forum much better at I am for preventing gel.
To control gel by making sure you get a full gel, you can put your oven on to a low setting as you soap and then, when ready, turn the oven off and put the mould inside (make sure the mould is oven safe!) but keep an eye on it. It can overheat, so it's not an idiot-proof method (I won't try it!
) or you can put it on a heat pad or wrap it in towels and put it some place toasty. It's of course possible to get a partial gel even with this - the key is PRACTICE and learn what you need to do with your recipe, moulds, house and so on. Alas no one answer will fit all cases with this
As for ash, you can put Seran wrap over the soap when poured, but then you can't do fancy tops (if you're in to that). Ash is just cosmetic, will go after a use or two in the shower and is really nothing to worry too much about for now