Something that I did recently and liked was mix up all of your hops together. Then, use 2-3 oz for bittering (60 min),2-3 oz at 15, 3-4 oz at flameout/whirlpool, and 3-4 oz for dry hopping.
I often use a blend for the whole recipe too. But rather than just toss them together and then portion them out (what it sounds like you’re suggesting) I weigh them out in proportion for each addition and then blend. Then you know each addition is really the same blend instead of hop potluck.
I like that name “hop potluck”. I might have to use that. This is what I was suggesting. I made a DIPA a few months ago like this and it turned out very nice.
For all my IPAs, 100% of the bittering comes from a single, large addition either right at flameout (for my west-coast IPAs) or after cooling to 160 degrees (for my hazy IPAs, where I’m going for less bitterness). I suggest you try this.
I get the right amount of bitterness while maximizing the hop punch–which is the whole point of an IPA, yes? Which steeping temp to use depends on how much bitterness you’re after. But with most of the “typical” IPA hops, I use about 1.5-2 lbs/bbl total.
For IPAs, and assuming that you’re going for the biggest hop punch possible, there’s no point whatsoever in anything other than a single, large hop charge at/after flameout. Sixty, 15, 10, 5, etc. min additions are useless. You’ll get the bitterness, but you increasingly lose the oils. You get the best of both worlds with a single, large addition at/after flameout.