Single VS Double truss rods?

[slowlearner]

I'm building a Fender bass VI style instrument on with 32" scale and I'm wondering whether I should 1 or 2 truss rods. The neck is 3 piece vic ash. Wondering what people have done with trussrods and what perspectives you all might offer me.

[Nick]

32" scale & a 3 piece laminated neck (in my opinion, but others may differ! (viva la difference)) shouldn't need 2 truss rods. My understanding of 2 is to counteract twisting of the fingerboard (as was the theory of the Rickenbackers I believe?) along it's length. I would say with 3 laminates (plus the fingerboard could be considered a 4th laminate) & such a short scale that this shouldn't be a problem as it is fairly stable in it's construction & the string pull won't be excessive. Two could be used for extra insurance if you are tending toward 2 & I believe Trevor Gore (a forum member & author) uses or has used a double truss rod system? So he may be able to add some valuable input.
Lets just say I've never used a double truss rod & have never had a return because the neck has gone funky, so I would stick with one but I do like double acting rods.

[Tod Gilding]

Pete , If your concerned about the neck, carbon fibre reinforcement may put your mind at ease.

[slowlearner]

I'm not so worried about strength. Vic Ash is epic where strength is concerned. What concerned me is getting the relief right for the top two strings given their tension. But I guess most 12 strings only have one truss rod.

[Nick]

What concerned me is getting the relief right for the top two strings given their tension.

Shouldn't be a problem Pete, especially as you are only using a 32" scale length (the string tension drops as you go shorter). All of my basses have used a 34" scale and getting neck relief with only a single truss rod has never been a problem. On my five stringers I have however run a couple of 1/4" square Carbon fibre rods down the neck (as Todd mentioned) as an added insurance just in case. If you have any concerns then the extra insurance could ease your fears.