John... Have you tried just using a piece of 1.25" tube (mine is 36" long) matched to a either a ball joint adapter or a 1-1/8 or larger socket, and just hitting them in?
I tried what I found to be a PITA threaded tool years ago, then moved to just using a jack handle (some are the right OD but a dedicated tube is nice) and a good fitting socket or BJ adapter. It is SO much easier and faster and I have yet to ruin a seal. Those threaded things are difficult to get the seal started straight I found, and then distorts the seal.
With the tube method, it only takes one semi-big hit with a 4lb hammer to seat it, then 1-2 smaller taps with it to get it fully into place. I wouldn't use a threaded installed even if 20 were given to me.