Rubella latex kit

[JOJOER]

We are looking at Rubella latex kits.  We were using the Sure-Vue select kit and liked that kit but they have stopped making this one.  We have looked at the Cardinal health, ASI and Sure-Vue Rubella latex kits.  All 3 of these have the same method and we would have to test all samples and the weak reactive control with a 1:10 dilution.  I cannot get the weak reactive control to work well on these using the 1:10 dilution.  The next step is to test it at a 1:5 dilution and I cannot get that to work well either.  Does anyone have any experience with these kits?  If so, have you had any issues like this?  Does anyone use any other latex kits that work well?  Thanks