Just purchase a 17" variable, 1984....
I just ordered all new bearings, my machine was used far less then yours and all the bearings were dry, as was the grease though out the machine. I used NSK 6203VV's, (rubber seals, non contact) ordered off Amazon for the two lower spindle bearings which are normal clearance vs more common C3. The remainder of the bearings I got off Ebay all Nachi with c3 clearance. Used Mobil Polyrex Em grease as this is compatible with the bearings.
The only ***** I had was the larger bearing in the floating housing just below the front variable pulley. They assembled it with a loctite equivalent (which was not visible) due to a large clearance between the housing and outer bearing race. A 12 ton press was useless, I ended up torquing up a 3 jaw bearing puller, popping that into a 250 degree oven. Bearing did not release in the oven but did once I applied more torque to the hot assembly; upon reassembly red locktite will be needed on this bearing, locktite is not needed on the remaining bearings. I made a spanner for the spindle nut from a piece of 1" angle iron, grinding to form two pins, took 10 minutes.
The VFD is a great idea, the lowest speed on these presses is still high for many uses. I would like to see if you can tap with VFD.
"I will have to remove the pulley system from the top and that will be a PITA"
That assembly came of easy, the top half pulley has a phenolic bearing, comes right off, bottom half was no issue either.
Most time consuming was the bearing just under the front pulley, the other bearing are on pretty tight but pull or press no issue