I used a big bar clamp to apply pressure to get my stuck ram moving. I soaked the locks and the mating line between the ram and the column with Kroil and let it work it's way in. After an overnight soak, the bar clamp was able to make the ram move. Once it moved, it was pretty easy to get it freed up. Just apply lots of penetrating oil and move the ram back and forth as much as it is willing to go without too much resistance. The oil works it's way into the contact surface as you work it back and forth, and pretty soon it moves full travel like it should.
You can buy or make a handle for your old pinion. If you make one, use a Grade 8 bolt, or at least a Grade 5. You can get even more strength by using piece of tubing that the bolt slip-fits in, cutting it square on both ends (or custom-fitted on the pinion end) so the tube bears solidly against the pinion. That will have the effect of using a larger diameter handle.
Once you get the ram moving as it should, you will find that the original pinion works just fine. You can set up the pinion to put the handle in a preferred position by backing off the retaining screw, pulling out the pinion enough to clear the gear teeth in the ram, turning it to the desired position, wiggling it back into engagement, and tightening the lock screw enough to keep the handle from moving in or out, but not enough to jam it in place.