Looking at getting one mainly for catching baitfish, but also to be available for a survival situation. Is there a model that would do double-duty that way? Anyone got any advice on what to buy?

I’ve seen them used a lot but other than that I’m not much help. Bet you could buy one cheap enough in just about any coastal Latin American country.

Might try to call memphis net and twine, they're usually pretty helpful

Dont get a small one. They open better if you get a 10 or 12 footer

What kind and size of baitfish, how deep the water, how clear?

I use a standard 6’ net, 3/8” mesh. Ot sure how many pounds per ft of wt on the leadline - but it is a standard net from walmart or academy. Use if for 4” shad mostly, finger mullet, and shrimp in water under ten ft deep. Mostly dingy water. I also have an 8 ft with 3/4” mesh and heavier leadline weights for larger mullet. It is decidely more difficult to throw - especially when wading - but it sinks quicker with larger mesh. Also for shrimp in deeper water.

Definitely not true in my case

Diameter only matters in your ability to throw it. A perfectly flat thrown 6 footer will out catch a poorly thrown ball of a 12 footer.

Other than that diameter should match the size shoal of fish you're after and conditions. In some of the sloughs I've thrown nets in anything much bigger than a four footer was risking getting tangled up on bottom.

Next is construction, then mesh size then weight on the lead line. First is a case of you get what you pay for next mesh should match bait size first sink rate second and lead line is your sink rate and closure to a lesser degree. Depending on depth you may need to balance mesh against lead to get it down where you need it.

That's all I use to get my catfish bait. I buy the ones made out of monofilament. My nephew had one out of nylon twine that I played with and didn't care for it. I'm convinced the all white net hitting the water scared off shiners/baitfish.
Keep them out of sticks on the bottom of the river and they last a long time.
They're cheap, at least the ones I buy are. Buy a 4' or 5' radius net, learn how to throw it and then buy a bigger one if you want to.
If your net has a tendency to snarl up on you, soak it in some fabric softener then let it dry out. It'll be good for all season then.
I see advertised some sort of plastic frisbee looking net thrower for sale.You don't need that. Take a couple of hours in your yard and learn to throw it. It's all muscle memory then.

I knew a gal that could really use the Castinets, quite a dancer too! OH! You said Cast Nets. Never mind.

https://m.youtube.com/watch?v=w6swnJXwEws

Instruction video. Makes it look easy

Remember your math - a 6' net is about 45% more area than a 5' net. I've had several 5' nets and will probably not buy smaller than 6' again. Keep in mind the nets tend to close up somewhat as they sink - so they get effectively smaller.
My go-to is a 6' radius mono net. used mostly to catch shad. I need to replace it - too many tears.
I also have a heavier weighted 8' net for deeper water. That net will wear me out in a hurry.
95 percent of the time, I am throwing off a boat - seats, trolling motors etc add an extra degree of difficulty.

Also realize it is easier to throw off an elevated platform. A ten foot net is a bear to throw standing knee deep in water. I have seen a lot of guys throw a net - and I have thrown one quite a bit myself. The guy in the video below is the king. AJ - on a charter for swords out of Islamorada, FL. A 14 ft net and he gets all 28 ft at full spread. Twenty ft deep water, he has to tie on extra rope to get to bottom. Stout dude and he said sometimes he has to get help to lift the net over the side from so much weight from bait

Just remember the size u order is the radius not the diameter. It got me once.Lol

our Walmart had them one year, they ended up selling them for 5.00 dollars

cheap ones on amazon, if you want to experiment before buying a good one.

I thought we couldn't use them here in MN.

Ha! Bernies going to.

They are legal in some areas, but this is not really what I am wanting one for. And of course if we are in an emergency No situation, what's legal is a little more flexible.

I think I remember that Wolfie was working with them.

Moosetrot

A six ft 3/ 8 net will catch all you need it for.