The big advantage of the sump over a canister is that you can clean sump things without turning off the filter. You can't do that with a canister ( unless you want a REALLY wet floor.
) The downside is they are going to be noisier because you want the splashing to oxygenate the water. You can muffle the sound somewhat by making a spray bar over just an open ended pipe but you will not make it totally silent. It does help if you have a a stand with a cabinet style base so that you can close the doors.
This a link to a flow chart for different sizes of PVC pipe:
https://www.slideshare.net/raju175/water-flow-pipe-sizes
Keep in mind that the flow rate is based on unobstructed flow so for example, if you have a 2" pipe that connects to a 1" bulkhead fitting so it needs to connect to a 1" pipe to go through the hole, you have to figure the flow rate based on 1" pipe not the 2". That also applies to any reduction in pipe size from the hole to the sump. So the flow rate always applies to the smallest pipe diameter in the line the flow goes through.
Regarding your drawing, I would reverse the use of the pipes. Make the large pipe the drain line and the smaller one the fill line. There's no need to use a ball valve on a drain line unless you are diverting water into different areas. ( more on this next paragraph.)
Depending on the size of the pump you eventually get, up may have more flow than your pipe really should have. It's never a good idea to restrict flow to or from the pump as it burns up the motor faster so in the pump line, place a Tee in the line with a valve past the Tee going to the tank and an open ended pipe from the Tee into another section of the sump away from the pump. As you adjust the valve so that the flow into the tank is not too strong, the excess water will naturally go to the pipe off the Tee with no valve and just go back into the sump.
So this is how I set up all my tanks and businesses that used a sump.
Hope it helps.