Omnistor 6200 fitting instructions to caravan roof

Hi

I want to fit an Omnistor 6200 or 6300 to the roof of my caravan (Bessacarr 525, 2010), but i can't find any fitting instructions or sizes of the fitting brackets.  Does anyone have any experice of this?  

I want to have it bonded rather than drilled.  i know Rose Awings will do this, but they are too far for me to travel and they can't come to me.

There are a number of different roof adaptors, but i don't know which one will fit as there are no sizes related to the information.

Is it simply a case of identifying the right bracket and bonding it to the roof, and screwing the onmistor to the bracket...?

Caravan is out of warrenty, so not worried about invalidating that.  

thanks