Unblockable sword will get you full combo punished by anyone who knows the matchup even alittle. b122 should be followed either by safe mid sword or the low/overhead mixup. ex sword throw is also good for applying pressure, should be followed by rc 114 df1
Other than that, look at his other stings too in the combo thread sticky, b122 is a fast punish but leads to little damage. His other notable strings are b14, f1b2 and 114 which lead to decent damage.
As for wakeups, they're just a part of this game, you gotta learn to block punish wakeups so they don't wanna use them. Either that or crossover punch them on wakeup and make the wakeup whiff.
*edit* Nvm just noticed you mean using the unblockable after you're already confirmed the combo