thats OK for a 2 pump system
BUT
if you use the "connect to right" terminal to connect two pumps together the will ALWAYS lift together even with other switches.
When you've drawn a circuit and checked through to see that you will sent volts where you want then to go you also must check that you haven't sent them where you don't want them to go.
Spot on of course

and to clarify for those who want to know, the unused terminals would go to the other pumps on a 4 pump system.
So on Tony's drawing...............
1st left terminal to right front pump, 2nd left terminal to right rear pump.
1st right teminal to left front pump, 2nd right terminal to left rear pump.
Also I wouldn't advise more than 24v at the switchbox as it might cook the dump coils
