That sounds like a pretty good time, better than I got with partial boils. Do you get a good cold break? If so it sounds like you at least have a good temp solution, but you are adding $5 to every batch of beer, so I would still look into some sort of chiller when your able.
I've been kickin that around. Really thinkin about I've probably spent at least $50 on ice this year. That's half of a chiller...S**t, I could have built my own by now...guess I better get started. I always figured I would get one once I went to 10g batches...hum?
I do get a pretty good cold break I must say...I can get it to drop pretty quick when I stir and dunk the pot up & down..just keep adding ice as you go.