Nester.
I would recommend Mark from Fill Express for any and all technical diving.
What makes Mark so good is that he has the chemistry and physics background and that is a great thing to know given the nature of tech diving.
Fillexpress.com Tell him Laura Parke sent you and he should take care of you.
A no-non-sense instructor. As he should be for that level of diving expertise.
Let me know how you make out in the end.
best regards,
Laura Parke
ScubaDivaLaura on Twitter