To my big disappointment, lower caster blocks came with a fair amount of play in them. That was predictable, so I was quick to implement my tested solution - tension rods. Simple, easy, super cheap.
This does not influence suspension work at all, except for a small dynamic camber, which is acceptable (and obviously better that a sh*t load of play).
Also, some shims were inserted into steering assembly. That gave me a very rigid rack.