Those are pretty good kits, though perhaps a little soft, compared to today's resin kits. Resin casting generally gets crisper detail than injection-molding.
Old Tamiya 1/35 are good for practicing basic techniques. You can find them cheap on the second-hand market, or even from modelers you know, who want to build the tank but not the crew. I like the old Monogram 1/48 aircraft crew figures, too. They're reasonably well-sculpted, and they finish nicely. But if I mess one up, I don't feel bad about stripping the paint. I use SuperClean for that, by the way. It removes or softens the paint quickly, and doesn't attack the material, whether styrene, white metal, or resin. I haven't found a formula of resin yet that was damaged by SuperClean.