Hello Williehayesjr,
as Dachs correctly says, the Reverb does not have a physical adjustment for your IPD. All i can say is, that the Index is a great piece of tech stuff. And coming from a Vive Pro (with Gear VR Hack) it was a great imrovement in the FOV and the size of the sweetspot for me - not in resolution. I could really look behind me for the first time flying VR. With the Reverb i was able to read everything in the cockpit for the first time flying VR. I mostly fly the f-18 and therefor being able to read everything without leaning in is worth to me a lot. But i have to admit, that i think about using the Index for flying the Huey. Because with the Index i am able to keep my head up and simultaniously look at the Altimeter with my eyes without lowering my head. With the Reverb i can´t do that.
Hope that helps you to chose the right HMD for you.
Yours Driskill