As mentioned, normally cast at 775F and no problems with my several iron molds. Now that that the aluminum mold is figured out (I think) it seems to cast a nice bullet, as well. And, drops the bullet out when I open the mold, which I like. Sprue plate is a bit funky, but something I'll either change or get used to.

Recently I bought a 2 cav Accurate aluminum mold, the 45-420P for PP my .45-70. I've been using a 20# Lee dipper electric pot and running the temp about 725. I'd have to cast about 15 bullets to make the pure lead bullets satisfactory. I just bought a single plate electric hot plate (med temp setting) to set the mold on while bringing the lead up to temp. THEN, I read on one of the casting sites, to make sure that you are keeping the sprue plate HOT enough by having a large amount of lead on it.  Think of transferring HEAT. Having just read that comment, I went down in the basement, fired everything up and had one of my best casting sessions ever. I do the same thing with my single cav iron .443 PP mold in a 20/1 tin-lead alloy.

I have several aluminum, Accurate Molds in 38, 40 and 45 cal. All double cavity.  I use a newer Lyman bottom pour lead furnace with the fancy temp control.  Using 20:1 alloy, I cast at 800F and get very consistent results.  The furnace has a mold heating stand adjoining the pot and it pre-heats the mold nicely.  It usually takes six or eight pours to get the mold hot enough for acceptable castings then I just keep going quickly (not fast) with each new pour and the mold performs as it should.  Seems like the temp of the sprue  plate has a lot to do with it; when it's not hot enough, the sprues are difficult to cut, but when it's right, the sprue plate will slice the alloy easily.
I did find the the most consistent results required the alloy pour to go straight into the hole without touching the sprue plate and then leaving a decent blob of molten alloy on top.  Using the bottom pour pot, I set the mold guide so the sprue plate is about 1/8" below the spigot; just enough so I can see the pour hit the hole and allow for a good molten blob on top.
I did try holding the mold directly against the spigot to simulate using a dipper and this worked okay, but with mixed results.
I don't know what equipment you are using, so I hope this helps.
Good Luck!
Mike.

Craigd it appears SSShooter has wore out our welcome so I think it best to ask him how he goes about doing what you have asked of me.