An RFI is undertaken at a point where it is expected there
will be a loose fit between the requirements and what a vendor
can provide. Not being aware of what is available in this
particular market, there will probably be things that vendors
offer that you have not considered. The information gathered
during the RFI will likely influence the requirements.
The number of vendors who will be approached, will probably be between four and ten. They will have been identified in the last phase. Phone each when you are ready to distribute the RFI document and make sure they are happy to participate.