Hiya,
I use a 'ball pin slicker' like this one:
Ball Pin Slicker | Pets At Home
In addition to a double sided comb like this one:
Double Sided Comb | Pets At Home
The comb gets right down to the skin and the brush helps maintain between combings by getting to the skin but not burning the skin due to the ball cap coverings. I did actually buy both of these products at Pets At Home and the brush, in particular, is wonderful for my cotton coated boy.
As far as conditioners, I have not found a human or dog conditioner which proved to be useful if you are looking to prevent matts.
A cut which reduces the length AND thickness with maintenance combing and brushing every other day seems to be the best strategy for us. Hope that helps!