Hi, those things can be a real pain, I had one in 1965. I remember reading in a manual that you can back off the big nut in the center "A LITTLE". And drive it a short ways, loading the rims both ways. Going around corners left & right to loosen the drums. Or a three legged puller.
Yep: Loosen the big nut in the center a couple of truns max. Then use a 3 legged puller the lug bolts hold to the drum/hub. tighten up TIGHT ,smack the puller center bolt firmly with a BFH.