Hey no shame in that. And I'm not annoyed don't worry about that.This a new area I’m working on now. Different pond and pump from the one running 5 maxis.
On this area I have a 1” foot valve through 15’ of 1” pipe at 5’ head to 1” inlet and outlet on the centrifugal pump. Here’s where I need to decide between 1” and 1-1/4” pipe to run another 150’ distance and another 15’ head. From there I plan on 3-4 zones, running mostly horizontal and back down the slope.
I have read enough to know I’m going to do this by the book, so I guess trial and error is my only course of action. It’s a fun project for me, not an occupation. I know this may annoy the experts and for that I apologize, but I don’t have 5k to drop on my side yard at this time. I do however have tons of water and some ingenuity on my side!
So the only concern I have about your setup is that 1" is too small I think and I think you'll have way too much friction loss. But as a rule of thumb I never have an outlet larger than my inlet. The last thing you want is to pump water faster than your pump can suck in. That leads to cavitation and burned up pumps. If possible I would maybe increase the inlet size to 1.5 so that you can run your 1.25 pipe successfully. With that distance and elevation rise you should plan for around 8-10 psi loss at the highest head if you use 1.25 the whole way. That's a very high ball park estimate not knowing how many heads on a zone.