I know the weedy lake locals like their Deltas, but I actually found that in all the places I visited, except maybe Budgie, 40 degree (Vector) leading edge worked fine when the wind and speed was up. At Fangys, I had to be a bit more careful about trying to start in the very shallow weedy spots, but once I was going I could clear the fin and be fine. No worries with Gybes, even in the thickest weed.
I recon 45 to 50 Degrees is fine pretty much anywhere, including Budgie. Can't see much use for the Deltas unless it's with big sails in very shallow water where you need the extra surface area. The Deltas do seem to be much better if you touch the bottom though!