I'll say yes to the 38 fitting your gear. Depends on packing it efficiently and possibly carrying the shelter by the bottom straps, though. I've not long been a fan of stuffing vs. using multiple stuff sacks, but it really does make a noticeable difference when you want to minimize pack size.
Friend of mine whose packing convinced me I could make more use of my Exos 38 is doing the Long Trail starting in a couple of weeks, and using the same pack with 5 days between resupplies.
I have both the Exos 38 and 58. Could have gone with just a 48, but wanted room for a week with a bear canister, which the 58 accomodates, and the most compact pack possible for short trips, which is where the 38 sans lid comes in.
Pack fit is a personal thing-doesn't matter what works for someone else. I place a lot of value on the suspended mesh back panel of the Exos, and fortunately, it also happens to be a perfect fit for me, so that's what I use.