Over the last 6-8 years between myself and friends we have caught well over a hundred halibut on jigs. Most of the fish have been 20 to 60 lbs. with the largest 115 lbs. I don't remember one hooked deep, all could have been released easily. We are using mostly 3 to 6 ounce Pirken or simiar type jigs with no bait added.
I use circle hooks a lot on baited lines (16/0) and find very few halibut hooked deep - probably 1 in 20. Most are hooked right in the corner of the mouth as expected. Securing a large fish with a rope round the tail should aid in removing the hook as well as using heavy leaders (I am going to try 150 lb.) will make it easier to hold on to the leader.
...Rob