Using the currently available frame data for Yang on the SRK Wiki, HP Slash-2 FADC U1 is a two-frame link.
HP Slash-2 gives 30 frames of hit stun. So, the frame advantage after HP Slash-2 FADC is:
Frame Advantage = (Frames of Hit Stun) - (Forward Dash - 1) - (Uncancellable Frames)
Frame Advantage = (30) - (18 - 1) - (4)
[*]Frame Advantage = +9
Yang’s U1 hits on the 8th frame.
Also, here’s a stupid, pointless, unnecessary combo I did the other day. I think I’ll be doing this (err, trying to do this) in training mode to get loose before playing: