Is 1202 a
model number? I'm not familiar with it, do you have a pic of the cab?
It sounds like it
might be a little small for a pair of big excursion 12" bass drivers, it depends on the porting.
In the real world practice there are certain characteristics inherent to 10's and 12's that make them different. A 12" cone has the potential to move more air than a 10" cone, and a 10" cone generally will have less mass (takes less signal to reverse direction, sometimes referred to as "quicker") and a higher free air resonant frequency; but in the "internet expert" world of
theory... factors such as excursion,
actual cone area, suspension, etc., and a 10 and a 12 being so close in size that it could be (and regularly is) said that it doesn't matter.
I will agree that it can be hard to make a distinction based
solely on cone diameter, but there is a
reason manufacturers
make different sized drivers, and that reason is that certain sizes are inherently easier to utilizes for specific applications.
So, as far as for a bass guitar cabinet, I suppose my opinion is "it depends".
Why aren't you a fan of ports in the back? That Ampeg should be a nice little cab.