Very interesting.................
I've not used oil squirters, however they will cool the piston. Below are a few other ways to do this also...
So will thicker rings (.062 vs. .043) this is how heat is transferred to the cylinder wall then the coolant, Chargeair cooling (for every degree drop in inlet temp you will see an equal drop in exhaust temp) don't believe me, ask Ricardo etc., More piston skirt contact area (again heat transfer to the coolant), and a thicker piston deck or crown (this is again how the heat is removed from the chamber to the cooling system).
Oil on the bottom of the pistons is fine but a few things to keep in the back of your mind when you do this.
If your oil supply is limited (say 5 to 7 quarts) you can overheat the oil so you might want to run a cooler.
Pay attention to your oil pressure. 8 oil squirters will reduce oil pressure to the engine.
Most race engines are concerned with crankcase windage. Shooting 8 nozzles at the bottom of your pistons rotating at 8000 rpm does what?
Also keep in mind that if you are not running a drysump or high crankcase vacuum you probally already have plenty of oil splashing on the bottom of your pistons.
The above information is my point of view regarding boosted engines at Bonneville. In-line 4's, 6's, & V-6's etc. are included