Short answer: Yes.
Disclaimer: I don't have a Lyman 55, but I do have an ancient Ideal No. 5, which is the parent of yours. But I can't remember if I ever tried Varget in it. I do throw a ton of Varget in my Dillon and my Uniflow.
IMO it's better than throwing IMR4895 so it can be done. I'd say plus or minus 1% is typical for me. If you're loading on a node that shouldn't make a big difference. Just don't expect ball powder accuracy.