I've bait-fished a spectra backed 40 with 65# sepctra and 40# mono. It did very well, I'd have no hesitation doing so again. The 30 is a narrower 40, so the drag, etc should be the same. I got 475 yards of 65 spectra on it with room for a short topshot, a little math should give you a round figure of how much spectra the 30 can hold.