Personally, I would get tired of constantly flipping a switch and then forgetting to turn it back off. I wanted torque converter clutch lockup to be automatic and natural feeling in my truck, so I designed an Arduino controller that based lockup on manifold vacuum and speed. In my opinion, the best commercially available approach is to go with a speed-based controller such as this one from B&M. The main issue this controller fixes is that you won't want the torque converter clutch to lock when you are driving around town at lower speeds because it will lug the engine.
https://www.summitracing.com/parts/b...44?seid=srese1
A manifold vacuum switch could be wired in series with the speed-based controller to make the torque converter clutch unlock when accelerating at highway speeds.
https://www.summitracing.com/parts/tci-cmp3766b
Here's a thread about how I started with a single vacuum switch and ended up with a custom controller:
https://www.67-72chevytrucks.com/vbo...d.php?t=822382