Sorry, this post is meant for lawtonglen:
In my opinion, if your caster is only +2.9 and +3.7 and the Ingall 594s are set to MAX available +caster THEN it does not add up. There has got to be something else involved here, the Ingall 594 setting instructions are NOT easy to understand without a lot of study and concentration, for slow guys like me anyway. :)
Maybe if you could take a picture or two of the top of the upper ball joints and post it here we might be able to add some insight. If and when you do take pictures try and get an angle that will help us see the slot in the bottom sleeve because it will be covered by the apron of the top sleeve.
I really want to help you here because I think there is an explanation but I gotta see the settings of the 594s.
ON EDIT:
On second thought, I am thinking the caster has been adjusted backward in that he has subtracted caster instead of adding caster. It is easy to confuse caster. The upper ball joint must move toward the rear of the vehicle to be getting more +caster. If you think of the caster wheels on a shopping cart you can get the idea you move the upper ball joint forward. NOT SO!!! Please do not give up now. :)