On my F1 I bought the DS valve seals, honda pucks and cruizin image gasket set.
I have done 400 miles and seems OK so far.
Recommend 2 stage head tightening ie tighten, leave overnight and check again.
Extreme care on M6 fixings, I use a 1/4 drive ratchet to "nip" up, having read reports of threads stripping even at specified torque.
Cruizin image set does not include pucks, but does include valve seals and will be using these on my K8