My experience with triblend is that it's best to keep your peak temp below 340 to avoid problems.
Can't say about WB, but my plastisol of choice for triblend is One Stroke ELT-S white. Cures at 280, very stretchy, can produce nice, lightweight, opaque prints. If you're looking to use only what you have on hand, check specs for cure temps; I'd use one that cures at 300 or lower.