I would not anticipate loading a bar for free-weight squatting the same amount of any machine. There are a lot of muscles not being used when you use a machine and the longer you're away from free weights, the harder it is to restart free-weight lifting -- and of course this varies from machine-to-machine.
It takes a lot of big and little muscles working together to balance a heavy weight on your shoulders and then add movement. Also, just the pressure of the bar on the shoulders/back takes some time to get use to.
Personally, I would just start up with free weights and not worry about the weight, just slowly work your way back up.
As for the restless leg syndrome, I've heard of this before, but have no idea what it is. The only problem I have to worry about are cramps in my legs if I overdo it.
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