What a coincidence! Just yesterday I cleaned and oiled the same machine as your green kenmore! I got it for $10.00. It weighs 1,000 lbs....
It was pretty frozen, at first, but I kept oiling, oiling and oiling some more while turning the handwheel. The handwheel would only turn an inch or two in either direction when I first began but by last night, when I plugged it in, it sewed like a bat out of *you-know-where*.
It's a pretty cool '60-ish looking machine with the avocado green. I'm going to order a new cord and pedal because the one that came with it started smoking...
I would definitely give the tan machine a try, too.