Oddly, one of the most significant differences between the 1219/1229 and the 1019 concerns the idler wheel.
In more than thirty years of repairing these machines I have only encountered one or two bad and unrestorable 1219/1229 idlers. On the other hand, I've encountered scads of bad 1019 idlers. They tend to turn into something "geological," with the result that the platter takes forever to come up to speed and the set will often stall during cycling.
As far as the arms, the 1019 arm does not work real well on most high-compliance, light-tracking cartridges -- although, if you have a Shure or Stanton with a quality brush/damper, it will work quite well. A good test is to play a record with a pinch warp (bump) near the edge. Watch it track the bump, and see how long the arm shimmies afterwards.
Most of the headshells for the 1019 have to be rebuilt. Each lead wire has two crimps, one at the connection to the spring contacts that mate with the arm and the other at the pushon that goes to the cartridge. These oxidize and cause signal loss. When I rebuild these headshells, I bypass the crimps and solder directly to the (burnished) metal. Also the little plastic nubs that hold the spring contacts in place tend to break off. I always reinforce the nubs with epoxy.
Hope this is useful.
Fred Longworth