I've been brewing partial mash for 5 years with great sucess, (2 gallon cooler with vegitable steamer as a false bottom 88% efficency) and have even used that set up for 5 or 6 AG 2.5 gallon batches that went well too. I got a rebate back from Menards and picked up a ball valve, and the screen to convert one of my coolers to a mash tun. I have a couple of drawbacks to my set up.
1. Me - I'm cripple, so brewing outside/moving 5+ gallons of really hot liquid...not smart.
2. Brew pot - I currently have a 3.5 gallon and 3 gallon brew pot, and there is no chance of upgrading to a larger pot until Christmas (Already convinced the wife to get me a keg set up for anniversary/B-day gift, not gonna push things now)
So, I'm looking at spliting the boils on the stove top. I've read some previous posts on this subject, but would like to ask a few questions to those smarter than I. Can I boil the 1st runnings in the larger pot, and do all my hop additions there (realizing I'll have to compensate for hop utilization)??
And can I boil the 2nd runnings in the smaller pot for 15 to 20 minutes to steralize, than mix both in the fermenting bucket/carboy?
I've read that mixing the first and second runnings is the best but see my reason 1 above for not wanting to do that. Thanks for the advice, can't wait to read what you have to say.

), bringing five gallons to boil on the stovetop will take a long time. You will definitely need a pump then. Maybe your plan of splitting the boil is better.