I would say contact Rod Jenkins directly and ask him.
That said, and this is a free opinion so you may not get more than you pay for. I believe the gazelle is quite a bit thinner since it only holds one set of limbs and a riser in a clamshell type configuration while the Rhino folds into a tri-fold configuration. Couple of reasons I prefer the Rhino: I really like the Rhino because there is plenty of room for extra limbs etc...looks like it would be somewhat crammed in the gazelle. The Rhino folds out into sort of a work table which I find handy. The side "wings" of the Rhino fold in towards the center of the case offering additional padding/protection for limb tips/bases etc. The Rhino also has separate sleeves for the riser and limbs while the gazelle only has sleeves for the limbs. I personally prefer the Rhino in all aspects but you may not need the additional features it has to offer.
Contact Rod (Shoot08s) here on Tradgang and you'll get the info straight from the man who makes them.
Either way, I don't think you will be sorry. Quality products, great design, and a great guy to deal with in every aspect.