... I've got the yoke off but the seal is a pain in the rear to remove....
No. It's a pain in the front! Because it's a front seal...get it?
Sorry, couldn't resist. That was like a slow pitch down the middle. And 'yes', I'm easily entertained.
...Are the double hook type seal pullers effective on these?...
Yes, they're great. Pretty cheap too. This is one tool every DIY home mechanic should have in their tool box. Take your time with it. I've removed seals that were really in there. If yours is difficult to remove, and it sounds like it is, the seal puller might tear a hole in the metal instead of removing the seal as the points are sharp. Just work your way around it, take your time and you'll get it.
Be careful with it on that jack. You might consider wrapping a piece of chain around it as a backup safety should it come off the jack.