It is hard to recommend a plug without knowing the exact types of water you're going to be fishing ... same can be said for color. Tads are always a good choice out here because they work in the widest variety of water conditions ... but they are not an especially deep-diving plug.

I have numerous colors that I work with depending upon water conditions ... probably what works well in drift gear will work fine for plugs.

I like a single barbless treble on the back ... siwashes do more damage to a fish on a plug, period.

Short lengths (35 feet) in fast shallow water up to 50 to 55 feet in slow deep stuff ... depends upon the plug type too. Again, something that there isn't a simple answer for.

You can walk them down, we've caught fish casting and swinging them across current, or you can use a side planer too ... but that might make you very unpopular as it kills the hole for everyone if you're fishing around others.

There are some books out there on the subject (from Amato), they're only seven or eight bucks, might be a good staring point for you. Good luck!