Bushings are great fun.
It's a toss up between rebound and turn - both are good but getting the perfect balance is the key.
Flat washers or inverted cups will allow the bushing more sideways movement.
Cones will squish easier than barrels.
Double barrels are great.
A lot depends on how long your kingpins are, but I think the more bushing you can fit on, the better.
Just don't tighten them down! If you feel you're having to crank down on the kingpin for stability it's going to be better to go up on the duro instead. A cranked down bushing has a lot of potential wobble-energy stored up, better to have a harder bushing and run it loose, imo - you get better feedback and more stability than a softer bushing cranked down so it can't move so much because it's under pressure.
Holey bushings are designed for Holeys and don't work so well in other trucks- tho' some folk put them in Bennetts.
Sabre bushings are great, but they need to be run-in. Cones are very very turny, green and purple barrels are great for a deep reboundy turn.
I think a cone boardside and a barrel roadside is a common set-up for slalom and pumping - the cone allows a very deep turn and the roadside barrel gives fast rebound.
You can tweak forever, but Sabres are as good as you can get in Sabres or Randals and Holeys are all you want in Holeys... so you just have the colours to choose, depending on how much you weigh and how you ride. Holey bushings won't work on Sabre trucks. I'd try green Sabres boardside and purple Sabres roadside.
Ah, that's enough from me about bushings.
