Put the tire on and drop it. It seems counter intuitive but it will give you the room to do it. Otherwise try jacking under the lower bj nut but its not as effective. Lastly you could cut 2 studs on the adapter flange and replace them with bolts later. That will buy you some more room to. I ended up doing the last two when I changed the boots on mine. but I wished I had just put the tire on as its easier.

1997 T-100 100k and counting Green
5spd 4x4 Ext Cab isr mod Aisin Manual hubs