What do you intend to do with the CRI rating that you will not be able to do with the FI(R) at a reputable RTF/FTO?
It is not simply the paying for a second rating. It is the setting up of your own RTF, the insurance and other costs and the fact that if you are doing some training in competition with the organisation you are hoping to fly with to have the FI rating unrestricted you are not going to have the best relationship - note that you have to tell them what other flying you are doing for FTL purposes!!!
Add to all that the fact that any CRI flying you do will not count towards the experience required to unrestrict the FI rating and I think that you may be complicating this unnecessarily.
I have to ask - Why are you in such a rush to set up your own training organisation when that will be limited to training pilots who already hold a licence? How many "hour with an instructor" flights are you planning to do independent of the RTF/FTO where you will work as an FI?
You must have a good reason - teaching aeros? teaching tailwheel differences?