Hey mate
Your best bet is to go a p1500 pump from Keene running on a 40hp motor on a diesel setup (kubota or similar) this will give you reasonable depth however if you want serious suck and hence greater productivity and depth ( less blocks) and wanting to with run a longer hose you can run x 2 p1500 on a 80-100 hp option in diesel. This will give you depth down to 50 feet.
If you want a petrol options going with 2 x 23 hp petrol’s using a p350s pumps will do well on an 8 and be essentially equivalent to 1 x p1500 pump.
The p500 keene pumps are a good pump but they are suited more for pressure and they will be underdone on a 8 inch setup if you want lots of suck. Plus running 3 x 13 hp petrol’s you will use a lot of fuel.
In terms of your powerjet setup id stay away from the triple jetlog setup. Your best to stick to a dual or if running 2 x p1500 a quad jet would be the best.
hope that helps