Adding sweetness and body

I shoot for exactly what you have for OG and IBU in my IPA (1.062 / 75).

Depending on personal preference of course, I believe the body is more contributory to the perception of a malt backbone than actual sweetness. I experimented a bit and have kind of landed on the following:

2row 90%
wheat 3%
carapils 3%
flaked barley 2%
crystal 2%

I know this is not too far off of the OP grain bill. But I was fighting a too thin of a body and this worked. I kind of think the flaked barley, on an ounce-for-ounce basis, makes the difference.