The rating of 10 GPM is usually the Best Efficiency Point. Yes it will follow a curve from 0 GPM to about 15 GPM, depending on the pressure or head it sees. Your well specs say a pumping level of 235’ with 0 draw down at 20 GPM. That is unusual to have 0 draw down for me, but it is good for you. It means your pump could be set at 313’ and it would still only be lifting from 235’. But I wouldn’t set it any deeper than 259’, so it is set above the perf. Anyway, go with 50 PSI (40/60 switch) instead of 40 because your house has 15’ extra lift requirement. Then you need a pump that will deliver 10 GPM at 235’ and 50 PSI. Or on a curve you would look at 350’ total head.
If the WM25 tank is still good, it holds about 25 gallons with a 40/60 switch setting. While using water, when the tank empties and the pump starts, all you have left is what the pump can deliver. So if you have a washing machine, dishwasher, shower, and a sink running at the same time, the pressure maybe getting low. Usually depends on how big a shower head you have. A 10GS15 will deliver about 13 GPM at that head, so you should be good, especially because you will rarely have everything running at the same time.
The GS has Stainless Steel top and bottom on the pump. The LS has brass, and the Bruiser has plastic. Other than that I believe they have the same impeller stack. That is a good brand of pump but, there are several good brands. That is not a bad price from an installer. You can do better but, should you? 259’ of pipe full of water, with a 50 pounds pump and 100 pounds of wire, everything wet and slippery, is not easy to do with a tripod. Poly pipe maybe, but it is probably steel or 20’ joints of sch 80 PVC. The only place to get a hold is at the couplings, so your tripod needs to be 20’ plus the length of the pulley, pipe clamps, height of the casing, and a little extra.
Best thing would be to pay an installer to just pull everything out and lay it down. Then you can put it back on poly pipe if you have some good help. Although for what little you would be saving, a good installers experience could be worth many times that. Anybody can screw and unscrew pipe together. It is the little things that you can’t find in a book or the Internet that can make for a good installer. What kind of connections to use, where and what to tape the wire with. Torque arrestors, cable guards, or is it better without those things. Watertight electrical splice? And just knowing you shouldn’t set the pump below the perf. Little things like that can make a big difference. Then heaven forbid you should drop something, anything down the well. You could slip and drop the pump and 20’ of pipe, but even just dropping a screwdriver at the wrong time could be catastrophic.
I am not saying you can’t do it if you want. And it would be a good experience. But 250’ of rigid pipe is not as much of a DIY project as 50’ of poly pipe.
I guess I should also say that if your installer doesn't know these things already, you might be better off doing things yourself. Anybody can drive a truck with a boom on it. But knowing the important things is what makes a good installer.
