Hi Stu, and welcome.
The kit the rest of us have is irrelevant, getting out and enjoying it is what it is about. We all had to start somewhere, and personally, I think that someone who jumps straight into a large RIB is missing a large part of his marine education
There are even some guys on here who should know better; they have RIBs AND the odd inflatable
Tell us more about what you want to use the rig for, what sort of load you want to carry, and where you will be using it, and although I am not the expert you may be looking for, others will be along to give you useful info