Excellent info for those newer to the game than you are, great post.
The pump pictured is from Harbor Freight right? I have actually had quite good luck with those. If they are working in clean water (post-filter) they last a long time, especially considering their low price.
If I may add to your final thought about reducing flow, its good practice to add a T between the pump and the ball valve, with the ball valve line returning to the pump tank. When you want to decrease flow, you open up the ball valve and let water bypass back into the sump. Saves your pump some strain from back pressure, and gives you some free oxygenation back in the sump to boot!