Rick,
They're about as simple as it comes, when it comes to fishing them.....If you can make a plastic worm weedless, then that's pretty much all you need to know on how to rig it.....Hook with a 2/0 or smaller thru the head of the Senko.....Then pull it thru the plastic, turn over, then back into the Senko.....Be careful with the thin Senko's because they're skinny and can rip.....They're full of salt and that's what makes them sink.....The fat Senko's (and there are lots of these available by someone other than Larry Yamamoto) are way more durable and are much easier to buy (Wal-Mart sells Yums).....Here in north San Diego, only Turner's sells the thin Yamamoto Senko's.....Oh, and they're pricey too.....$8.00 a bag of 10.
Don't throw them away when they rip either.....You can Wacky Worm them.....That's where you hook them in the middle with a short shanked octopus type hook.....Really a good technique in more open water.
For your kind of fishing, I don't see them working as well (if it's just canals)....You fish them very slow and fast moving water is not your friend.....Fig Lake or any of the slack water places would be where I would use them out there.....Flipping tules or grass holes is great.....They're totally seedless and sink slowly.....If the water is a little deeper, then as mentioned before in this thread, you can add a nail or lead nail.
I only use 3 colors.....Green pumpkin (BF), Watermelon (BF), and Watermelon (RF).....I like green pumpkin red flake & purple flake and are really good, but almost impossible to buy.....These are Yamamoto colors.....Each brand makes these colors, but are slightly different.....Another color may work better for you.
Lots opinions and techniques.....lol