Done using homemade PStick with Hauppauge HD PVR to check. Cammy/Ryu vs Marduk. Videos to follow.
Tagging
Short run in, not cornered
Tag input F0, attack input F73 - no action
Tag input F0, attack input F74 - attacks
Long run in, not cornered
Tag input F0, attack input F81 - no action
Tag input F0, attack input F82 - attacks
Short run in, cornered
Tag input F0, attack input F73 - no action
Tag input F0, attack input F74 - attacks
ABCC combos
Opponent cornered
Hits F61, attack input F137 - no action
Hits F61, attack input F139 - attacks, hits F142
Self cornered
Hits F61, attack input F135 - no action
Hits F61, attack input F136 - attacks, hits F139
tldr; depending how close you are to the edge of the screen, your run in can be up to 8F longer, your ABCC partner can hit 3F later.