I've thought about this the last few seasons since you mentioned that. I think such a project would be very interesting. But I wonder if one might need to adjust one's expectations. What do you really want? Shelling, snow, snap, or soup? Customers seem to want snap peas above all others.
For example, for weevil or other pest resistance you might need to select for tough leathery skin and thus perhaps aim more for shelling types rather than low fiber snow peas.
Perhaps other traits like tannins, anthocyanins, or orange-pod or orange cotelydon genetics might deter such pests in other ways through chemistry. Though those genetics may also affect flavor and palatbility for humans.
It might be worth asking an entomologist what he might do.
Mass selection might work if you're willing to dig through and mark which ones appear to have no damage. But i'm thinking separate rows with trellises/chicken wire (if you want to) and just mark down numbers of pea weevil damage. That would require paper and taking notes though
I'm thinking stick more toward shelling types. Maybe the old purple podded shelling Capujiners. It seemed very leathery to me.
