2 problems, need some help/advice

Casting: So I've been using an older Lee bottom pour fire several years now but upgraded to a Lyman mag 25. Couldn't get smooth boolits to save my life. Had a Lee 356-125 6 banger that other as long as it took to melt solid lead ingots and it to be a steady 770 deg but even after 15 throws all I got were swirls. Even tried another mold, Lyman 429 250 HP mold and still even after 15-18 throws still swirls. Didn't have this issue with the Lee.
Also I really want to try the 312-155 but my of mold wouldn't cat a good pill no matter how hot or cold. My 6.5 CM Lee mold is the same way. Irks me to no end.

Lubing/sizing: with the Lee 356-125 and 358-158 swc, I almost always get a smeared side on the cast even sizing. Using both of the recommended to punches for the 358, but they're not a good fit. Modified one that's close now but still smeared. The 356 smeared with the correct punch as well. I've tried tightening everything down and applying even pressure but nada.

Hard to say at this point what is going to work.
Especially considering I don't own a bottom leaker and have not for 30 years. Once was enough.

I do all my casting with a Lyman dipper and a little lee dipper pot.

Just off the top of my head though I would say give your pot another 5 minutes to warm up before casting. I do find a side hotplate handy for preheating molds, especially the larger 6 cavity ones. I do not have mine tuned in that well but it does come up to temp faster, takes fewer casts before it is producing good boolits. But some molds just seem to want to make boolits, others need to be coaxed.

I think your pot is suffering from random dial placement.
770='s sumthin else.

let it warm up for a half hour then put a thermometer in the melted alloy.
at 770 you should be seeing a gold sheen form on the surface this would be the tin oxidizing.
set the dial to match the thermometer.
I had to do this with my magma pots, one was pretty close one was off about 50-F.
I then took a paint marker and made slash marks on the dial for various boolit diameters, I could then run the same pace but put more or less heat in the cavity's.
the slashes are between 680 and 725 but are easy for me to glance at and adjust from the side.

Isn't that Mag 25 PID controlled? Seems like another fellow had problems with the temperature on his. Wonder if they've got some kind of problem with either their hookup method or the PID itself. 770° is WAY hot. I've got 3 PID's and a VOM and switching TC's around to all of them they're within a couple degrees of each other. I had to adjust my dial thermometer that was off!

Did you pre-heat the molds(esp. the Lyman)? concentricity is a problem with the bottom first sizers and why I use a STAR, some folks have "floated" the top punches on the Lymans/RCBS. Machine a small groove on the stem of the punch and use an o-ring to hold punch and it will float some, just tightening the set screw may be moving you off centre.