Fox Vanilla R spring

Hello. Ive just purchased a 2010 Vanilla Van R rear shock with a 300lbs spring in 8.5 x 2.5size, it came with a 300 x 3.24 spring. Its mounted on a 2009 santacruz heckler and according to their web page they recomend a 300 or a 350 for 120 lbs (my weight). Its a little on the soft side but nothing I cant fix with a $30 little stiffer spring and I want to order a 350. Im checking the usual webshops (jenson, beyondbikes, pricepoint etc...) and I can only find a 350 x 2.8 spring, I cant find 350 x 3.24, will this spring fit my 8.5 x 2.5 Vanilla. Im not sure if the 2.8 refers to the stroke travel or the size of the shock, in fact there is no vanilla or dhx shock with 2.8 travel. Does anybody know which spring do I need to order if I want a 350lbs for my 8.5 x 2.5 Vanilla, I dont care if the spring doesnt goes almost all the way to both sides of the shock (like now) as long as it has enough length to preload the spring with at least a full turn without the need of spacers. Thanks.

Bernardo