Ok I just tested it with the help of
Joker8417
for the regular telekick, it seems a lot easier to block it high then do a D1 or Standing 1 depending on how late the opponent throws the sai. If it doesnt throw the sai at all then it's easy punish.
For the EN telekick, like I said you after you block the first kick high, block the second hit low then do D1 xx gunshot~slight dash into D4 xx roll toss. The second kick seems to have some crazy stun in it. I find it a lot harder to punish the second kick if the opponent doesnt do the sai. With the delayed/instant sai I was able to punish it. I wish I had a camera to record it for you.
So for punishment based on landing D1, you should be able to do the followings:
1. D1 xx roll toss
2. D1 xx gunshot (possibly followed by standing 4)
3. D1 xx baton sweep (kinda doubt it. I need to experiment with it more)
4. D4 xx gunshot ~ D4 xx roll toss (I think the D4 is for late sai)
5. D1 xx gunshot ~ D1/D4 Roll toss (20% damage)
Now im pretty sure you can do a variation with EN gunshot and roll toss for extra damage.