Beartooth is using LBT molds, at least for many of the bullets he sells, as I sold him a lot of them before we had a falling out. I don't know what he says he uses for lube, but it isn't LBT lube, unless he is buying it on a merrygo round, so to speak, which he did with many of the molds he has and lube for several years at least.
By all means, buy your own mold, from me of coarse, and have me fit YOUR gun, so you KNOW you'll get performance. The cost will be forgotten once you start knocking out precision bullets for pennies each.
A 300 gr WFN will work like lightning on any north american game if you kick it out the barrel at 1200 fps. Nothing wrong with a 280 gr and I'd go chasing moose with it, personally, but most shooters feel more comfortable with 300 gr and heavier.
If the antique Lyman is all there and not broken, you will have a good one, better than their new ones, if it's over 40 years old. It takes the same dies that are being sold today, and uses hollow lube sticks. Get our Blue soft, and it will flow through smoothly. Best dies to buy are RCBS, which fit fine, and have better lube ports than Lyman dies. Best way to give you more information is for you to have a go at it then ask questions so I know what you don't know.