Either way, tab or standard notation, is just fine as a way of learning solos that someone else has created. But in bluegrass jamming, people have to “think on their feet” and learn to come up with solos based on their ability to follow chord progressions with notes that fit in the chords, and put in melody notes or pre-learned “licks” where they can. So we actually don’t use written notation at the camp at all, but work on developing ear skills. Since you are already a singer, you probably can already find melodies by ear, and that’s the kind of thing we encourage at the camp. Since we keep the tempos nice and slow, learning to solo this way gets a chance to happen at an easy pace, and there are lots of chances to try solos on good but simple bluegrass songs.
You’ve probably noticed in seeing other people play bluegrass, that people are not playing from paper. Nor do they usually have from-paper solos memorized. They make do using the above methods, and that’s what we teach at the camp!