Well, I started with a Shurflo 100 psi. Lasted 8 months & the bearings failed from heat
Bought cheap 40 psi off eBay (24v ones are real cheap!)
I use 100 m of 6mm clear hose which snakes after me a beaut.
I've also now been using an accumalator for 3 months & find that a 75 amp hour battery can last 4 days between charges.
Also the 40psi pump I choke back the flow for most jobs.
So why 100 psi?
Kevin.