Regarding the Oberth, some have asserted there are two differently-sized versions. Treknologically, we have precedent in the Klingon bird-of-prey. The OCD in me wants there to only be one. What is the feeling of other folks?
I still think the larger one fits better, if only because the smaller one doesn't make a lot of technical sense, ESPECIALLY if we assume the sensor pod underneath really is a huge sensor array like a lot of us have always assumed.
This is turning into yet another episode of "But the MSD is really tiny!" which is a similar issue with the ever-rescaling USS Defiant: the entire design simply makes more sense as a much larger vessel, and the only evidence for a smaller size is a three-deck MSD. If you're willing to take the MSD as being not necessarily accurate (which the FIRST Defiant MSD already was) then it gives you more room to work out a more realistic range of sizes.
In the end, let's face it: unless the MSD was drawn by the guy who actually designed the ship -- and not farmed out to the art department after the fact -- it probably isn't going to be all that useful.