I have 5 sets of 13x6 wheels for my 71 ITB Capri. 4 of them are alloy, my favorite set are the lightweight steels versions. They are lighter than my allows, and seem plenty stiff for my needs.

Oh, I might mention that I've heard that FWD Diamond steel wheels can be much heavier than RWD steel wheels. Something to do with the thicker hub required.

check with Diamond, but I love my Diamond wheels.