Orange whip has been sweet for developing rhythm and strength. It's been great for warm up and stretch on the range. The half-slap drill needs punch. Unfortunately, the needed fast twitch muscles deteriorates with age. The net says athletes that rely on explosive power (e.g. sprinters) build fast twitch muscles using what's known as overspeed training.
So, built a little fast twitch training club, basically a stick with grip built up on one end with athletic tape. It's designed to be swung as fast as possible, either single handed or with both. A couple of big nuts are taped at the other end to keep shoulder sockets from popping out. Makes a nice sound at speed, and, if swung properly, good woosh at about 6 to 9 o'clock.
Initial tests show left arm is fast. Right arm super slow. Being right handed, that's interesting. Will add this to the training program, along with fast swings of 3 wood with a small donut.
Need a way to measure progress. Hmmm.