A recirculation loop does not need much power or head. The pump in mine only draws 9W, and it works fine pumping water from the basement up to the second level without issue - it's not like it has to prime the loop...it's already full of water.
THere's at least a few ways to do recirculation. One is to have the pump run most of the time, and use a thermostatically controlled valve at the end of the loop (or loops). That will open or close as it senses hot water at that point. That would use one pump back at the heating source.
Or, you can use multiple pumps, one on each loop. Everything in my home branches off of one line, so I can get by with one pump and one sensing device (in mine, they're combined, but could be separate). It just so happens that I use one at the furthest point rather than near the WH. It has a built-in aquastat, and an internal timer so only runs during the normal use times. It turns itself on when the inlet water temp is below about 85-degrees, and turns off when it gets to 92. They make a version that is adjustable. Some of the others use a thermostatically controlled valve and most of them shut down the flow when it reaches 105-degrees or so.
With the system I have, the first time it comes on in the morning, it might take a bit over a minute to get warm water there (the shower is closer to the heater, so it's hot), and then, it only runs somewhere between 3-6x per hour for about 45-seconds or so.
The copper institute says you should never run hot water through copper pipes faster than 5fps, and that's only about 4gpm on a 1/2" line, or 8gpm on a 3/4" one. If you DO run it faster, expect several deleterious results: water flow noises, potential erosion of the pipe, and, your WH won't like it, either. Plus, if you size your pump for fastest results, you'll be using more power, and the pump will cost more, too. Keep in mind that any pump will need either SS or bronze, which ups the costs a lot over a pump designed for say hydronic heating...potable water will contain some oxygen, and that will rust out a CI pump body or impeller. In a heating system, once filled, the oxygen reacts with the iron, and then, stops since there's none left, so a CI pump can work.
You don't really want a large pump. Head isn't an issue, since water is just going around a loop, so whatever you push up is being aided by the same amount falling back on the return side, sort of like spinning a bicycle wheel...you only have to overcome friction, not gravity.
YOu could use a motion or a manual control to turn the system on, but in the system I have, I just let it run most of the day, and the timer disables it when I don't expect to be home or am asleep.