Mate, if you're just going down to a inlet in Mando', YOU DO NOT NEED A THROWER.
If indeed you are only going knee-deep, you're not going deep enough for them big ones.
Take it from someone whose weekend ritual is to go down with a bunch of mates and catch bag within two hours. Record is 28 minutes.
This is what you need.
Not a completely pure flooder like the eBay zoomies, but something with a lot of spill, and really bright.
Mr. Krab is a crab, he's secretly trying to protect his own species. You are going to miss a whole lot if you have just a tiny identification area.
With regards to SMO/OP, I'd go for OP, it'd smooth out the projection and really helps shape identification. SMO is more prone to artifacts if it doesn't sit perfectly and rings on the beam won't help you identify your prey.
Here are my recommendations:
Charger (No, you can't use a normal charger.) - Nitecore Intellicharger4 v2 from FastTech and AU Cable (if you don't have a spare lying around.
Optional - a nice big Li-Po Charging bag.
Submerged Torch (for mounting on the end of your scoop net) - Trustfire TR-J1 or TR-J2 (They aren't driven very high, around 2.2-2.4A on max) nb. remove the attack head bezel to get a nicer, wider beam. Go for the TR-J2 because it's cheaper and comes without the bomb battery and charger which are useless.
Handheld (you want something relatively small with which you can still use two hands to scoop) - I lend out Solarforce L2P, L2N and L2T, even a Ultrafire 504B all with ~2.4-2.8A, some of the 2x18650 capable. All have been dropped in the water sometime, all have not had any ingress whatsoever. Just keep those O-rings lubed.
Headlight - really anything >500lms running on 2x18650 batteries. I use a Nitecore HC50, which I only put on medium to see where I'm going. Your first instinct if you miss something will be to turn your head towards it. This also could potentially replace your handheld and leave both hands free for battling. It makes you look like an idiot, especially if you have puffy hair, but c'mon, it's crabbing. I lend out this and this.
MONSTER, for the unarmed bucket b*tch - I personally assign a Roche M170 to whoever is holding the
captives crabs. There are better alternatives available now, the Solarstorm SP03 claims 2m submersible.
Batteries - I am personally a bit wary of using my precious Panas in the water. I also wouldn't use any included batteries or chargers. Be sure you know what you're doing, these are volatile little suckers.
Biggest bang for buck, Sanyo UR18650FM Flat-Top and Button-Top or Panasonic NCR18650.
If you're feeling REALLY adventurous and cheapo - buy 2 of these and take them apart. They have 8 Samsung ICR18650-28As each. You might need some of this shrink wrap if you damage the original casing though.
26650s - Trustfire. Some people will flame me for this, but these have been proven to be very decent. They fit into the Convoy L2, but I don't think the L5. King Kong 26650s are slightly more expensive.
Accesories - get wrist straps. Made for WiiMotes, phones, whatever. It'll allow for you to drop your handheld at any moment and go HAM for that monster that's belting away. eBay, 2 bucks for 10 pcs.
In bad conditions (last week Friday there were 25km/h winds, high tide around 6:30, arrived around 8) I use a full length Convoy L2 (as big as a 4D Maglite). Has a nice spot for depth penetration a nice even spill.
An overly bright spot in other conditions is counter-productive as it distracts from identifying objects in the spill.
Currently out of stock everywhere, but a Convoy L5 is probably just as nice with a bigger spot.
ALL PRICES ARE IN USD WHICH SUCKS FOR US RIGHT NOW.
Don't forget your crab gauge. Happy Hunting.
I shouldn't be telling you this. Less crabs for me.