The only way you will be able to figure out what you want/need/can afford is to get on the phone and start calling some of the net people.
Google: Memphis Net and Twine NIchols Net and Twine Delta Net and Twine Miller Net Company
That's all I got from memory. You are looking for something like a seine with a mud line and floats. Mesh small enough that it WON'T act as a gill net. You want the net to be about 25% taller than the deepest water that it will cross.
