I can only attest to time of year, as I have only used one guide, one time down there and it didn't go so well (guide's outboard blew up the day before we showed up, so he tried to get a loaner boat... and so on and so forth, but we still caught fish, just only got to fish about half a day).
When I lived in Lafayette, we used to always go down to Venice right around Halloween, I have been down there in mid-May as well. We seemed to do better in the fall, but I do not think there is a bad time to go really, especially if you are going with a guide.
The weather was also always/usually nice in the fall. During April, May, and June, you can almost set your watch to the afternoon thunderstorms, and they aren't just little showers, more like squalls.
We always fished the SW Pass, and you just can't beat catching a largemouth one cast, a blue cat on the next, then a stingray, then redfish, ladyfish, flounder, speckled trout... You just never knew what you were going to pull up next. Way too much fun.
I haven't been offshore, but I watched a show the other day that they were catching 60-100 lb yellowfin in November.
That was probably one of the least helpful posts ever. Sorry.
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Ocean Kayak PBG, Humminbird 160, square center hatch, deck lighting, all that good stuff... basically more money in accessories than I spent on the boat itself, and it came with the seat and paddle, so that's saying something.