FWIW, most engineered recirculation systems do not run the pump until you have full hot at the sensing point. Yes, you may need to do that in a commercial building, like a motel, etc., but generally, the ones I've looked at for a home, do not. The one I currently have is not adjustable, and it shuts the circulation off when the sensing point gets to 96-degrees, and doesn't turn it back on again until it drops to like 88 or so...I may be off a degree or two on it, but it's in that ballpark...this is to minimize the heat energy losses, but gives you instant warm, and hot many places. In my situation, my upstairs vanity is the furthest from the WH, while the tub/shower is closer. When the timer enables it to run, I'll have warm at the sink instantly, but because the shower is closer, it gets hot quicker. It's only got a very small motor (like 9W), and runs maybe 45=seconds about every 15-minutes or so, depending on the season.
I've seen some run the recirculation until 105-degrees, and my original one that died after nearly 20-years (the check valve died, not the pump, but the company had gone out of business just the year before so I couldn't get the proprietary part, and I didn't feel like modifying things) was adjustable, while the new one is not (although they do make a model that is).
Without the pump (if I happen to get up early before the timer turns it on), it can take like 90-seconds to get hot water upstairs...I much prefer the recirculation! What you do NOT want to do, is over pump it...high velocity, hot water flow can literally erode the pipe from the insides, plus, the pump costs more as does the electricity to run it. Pex has a maximum recommended flow velocity (it's higher than copper's), but on copper, with hot water, it's a maximum of 5fps. With the ID of copper, that's only 4gpm on a 1/2" pipe, and 8gpm with a 3/4". You'd have to check the pex manufacturer's design guidelines for velocity. Keep in mind that higher velocity also means more dynamic friction, and thus, more dynamic pressure drop.
You may find that hot water recirculation systems eventually become mandatory to help save water. They certainly do that, but if combined with a timer or manual activation, can also save power. Even with your own well, every gallon you pump out of the ground, you're paying for the electricity to pump it.