how far do you hit your clubs? that's key. the way i think about it is...the longer you hit them, the less you need clubs up top. i don't think many average golfers hit GIR's over 215 yards, so it's okay to have a little bit larger gap up top than down below. plus, how often do you need to hit the ball over 215 yards unless you are either playing from tees that are too long for you, or going for a par 5 green in two shots?
i basically consider 215y the top of my accuracy level, so i try to have no more than 15y between clubs from 90y to 215y. after 215y you can do a 3w or 4w and driver. some people even use a 2h. chances are for me, even though i can hit a 3w 240y, i won't hit a green from that far away but 1 out of 10 tries. so that distance isn't one i need to be super accurate with since most of the time i'm chipping from off the green anyway after said shot. so it wouldn't make much of a difference if the 3w for me only went 230 or instead went 250...i'd still be chipping from off the green.
i'd say fill in those gaps to 215y in no more than 15y increments first, then start paying attention to your rounds and how often you really need a club to go more than 215y within reason. if you're hitting a 4 or 5 iron 215y already and hit a lot of GIR, obviously your point of accuracy is higher than the average golfer from that far out, so adjust your needs accordingly.