Herman, it seems to be you are a bit confussed with the CAACI rules and OTAR!
1. It depends on your license. For example: You hold a valid german issued JAA ATP lic. with a valid T/R in it and you insist to fly a VP-C reg. aircraft based in germany!
Than you only need to send the validation application form, a notariced (or TRE stamped) copy of your lic medical and a letter of the owner to the CAACI. Thats it.
2. OTAR! Yes OTAR is a bit more complicate but first: If you want to push your owner to act under OTAR requirements than firstly he has to apply for OTAR 125 and OTAR 39 and do all the paperwork that we all hate.
Because to apply the OTAR rules you need a company FOM! first. And there you can define your own trainings manual and trainings devices.
For example: What if there is no simulator for your aircraft! Like the Mitsubish Diamond Mu300 (there is worldwide only 1 simulator - FAA approved. With a german JAA license you are not approved to do the LPC check on it to revalidate your T/R)
Therefore you can write that information in your own FOM and send it to the CAACI to get it approved. After approval act like written.
I know it is much more complicate with OTAR, but I figured out at the final end VP-C reg is easy to handle when you know whom to speak on that island.
And it is not the CAACIs fold, that your owner doesn`t take care of the rules. Finaly there are AUDITHs! needed to get the next CofA approved because of missing OTAR requirements it wouldn`t be possible for him. So if that guys doesn`t take care of the requirements he will be stucked on the ground latest by next year.
I know that doesn`t helps you right now, but it should give you a picture of what are the options.
If somebody has questions how to handle cayman islands reg. feel free to ask me. I am dealing with those people for several years
Rgds