I have a simple test app that just displays the orientation and accelerometer values (used for initially discovering the confusion in orientation between iOS and AppGameKit, which has been fixed). I have the app in both Tiers.
In Tier 1 iOS, the v1076 app takes 2.5MB installed (including the start up images required by Apple, about 365KB). The same app in v1088 takes 5.1MB because of the overhead for the social media stuff, and probably the extra interpreter stuff for the 3D processes. As a comparison, the Players (which handle receiving broadcast programs) run 6.9MB and 13.0MB for v1076 and v1088, respectively. Within the Xcode build directory the v1076 test app is 2.6MB, the v1088 version is 4.9MB.
For Android, the v1076 Player apk is 2,775KB and the v1088 Player is 3,577KB. The v1076 test (like the one for iOS) apk is 2,902KB producing an on-device size of 5,440KB or 3,230KB, depending on device.
The on-device sizes for my current Tier 2 project tend to run small compared to things like Jelly Defense and Angry Birds.
EDIT: Tier 2 and Tier 1 are similar for small projects.
Cheers,
Ancient Lady
AGK Community Tester and AppGameKit Master