My home lake on Livingston is no different than Twak when it comes to wave action. Probably worse. Get a deep V hull and respect the water. The south wind blows into my dock on the main lake and I have seen many sinking/capsized boats float by during bad storms. with 20k you may be looking into a good used boat. The lighter the boat, the more it will bounce around. We have a bass tracker and a 23 ft hurricane center console. The hurricane is over 4000 lbs and takes waves like a champ due to hull construction and weight. Rarely do I ever take the bass tracker out on that lake. Its like being in an empty beer can bobbing in those waves. A used hurricane gs211 may be good for your situation. We have the 23 ft version and have caught god knows how many white bass and stripers out of it. More than enough seating. Can ski, tube, fish, cruise. It does it all. I think ours is a 2004 and has been holding up great.

Even a 17' aluminum deep V boat is a pretty big boat. I have used my 16'5" aluminum deep v many times on Twakoni without problems. My general thought is my boat can't take it I really don't need to be out there.

Lots of folks talked about the size boat you need. I agree with the guy that said get the biggest that you can afford. No one mentioned motor size. Be sure to buy the Max power that is listed on the Coast Guard tag, since you want to ski with it. I am 68 and owned boats from 15' to my current 22' pontoon. room is one of the key factors I look at. If you can afford it the new tri\toon boats with the big motors will do anything you want to do anywhere.

I fish Tawakoni with a 17ft fiberglass bass boat. I fish that lake knowing I can't venture far from the ramp with that boat. Tawakoni can turn into a beast in a hurry.

There is a big difference between a 17' bass boat and a 17' deep v.

There are some very nice used Mako 21', 22', and even up to 26' center console deep V boats down in Houston to be had for under $10,000.
There is a Mako 238 Walkaround posted on Dallas Craigslist for under 5,000 now.

Those older 1970 to 1980 Mako's were built like tanks. It might take a little looking on Craigslist to find the right one but they're out there.
Checkout Classicmako.com to see what some people have done with these boats and what they look like.

I have a 1972 Mako 17' Standard center console I picked up in Houston and a 1972 Mako 19' center console that picked up inn Allen, TX.
I use both of these on Lake Lavon - take the 19' when the wife wants to go fishing with me.

We just got a nautic star 224. We like it alot. I think they have cheaper smaller versions in your price range. We were looking at deep v aluminum and went with the Nautic star instead.