You can get eccentric bushings with more offset up to a point. Hopefully you aren't already at the limit. Aligning those trucks isn't hard if you know how to do it.basically there are two caster settings for each bushing when you set camber correctly. Spin it til the camber is right and then read caster. Need more caster? Put in a bushing with more offset and repeat.
There used to be charts for which one to use for a given amount of change.going to a ford truck center might be your best bet.
Just don't get the two piece ones to help out your alignment guy.they are a pain.
I’m pretty sure the bushings are 2 piece adjustable. They were already in there. Maybe I’ll take it to someone that specializes in I beams and can just put the right bushings in to give me the desired caster