Keep in mind when you see a throw net in the store and its advertised at a 4' net, it will be 8' in diameter.
I've caught a zillion shad with a 3' throw net, mainly because I didn't have a casting deck up front until now. Probably go with a bigger net now. The shad don't do well in a live well for me anyway. There are some chemicals you can buy to put in there that will keep them alive for awhile. They throw off their scales, and puke their food out while beating themselves against the live well walls, and in short order are dead.
The only way I've found to keep them alive for awhile is to just put a dozen or so in a large live well, instead of a net full of 50 or so to keep down the overcrowding, OR buy a dedicated shad tank.