You will love those SPC UCA's! Hopefully you got them from Peter Bergman. I put them on my avatar, dialed in 3+ degrees of caster, and have a car that now leaves straight and goes straight. Only you can decide what lift amount you want to use to set the toe at. The MP book goes through that as you cannot be perfect under all values of front end lift. As the front suspension drops, those tie rod ends don't get shorter so they tend to add toe-in. I think I used 1" front end lift to set mine up as I figured the majority if the 1/4 mile would be spent in that range. But I mapped it at various lifts so I'd know what it does.