All Friendly SGP Users,
I wish to extend my sincere thanks for your help and support. Today I am happy to report that I have successfully been able to add two SBIG cameras. ST 8300M with corresponding FW-8300 Filter wheel and the SBIG STi autoguider.
For anyone who may trip upon a similar issue, here is what I did based on many helpful reviewers in this friendly community here (once again sincere thanks to everyone for the superb support).
In Equipment Profile Manager - define main Camera (ST8300M), Filterwheel, Focuser, Telescope (which is Paramount MX via The SkyX ASCOM driver), Platesolver (in my case PS2)
When it came to Autoguider in the EPM, it opens up PHD2 window with a previously defined PHD2 profile, I had labled as OAG.
It is here where I actually connect to the STi autoguider. BTW the first time any client software tries to connect to two available SBIG devices, causes an OS prompt that allows the user to pick which of the two should be used. In this case I used STi
Next I clicked CONNECT ALL (which includes the Mount)
Go back to EPM saved this profile
And this is it.
My sequence from this profile then connected to the ST8300 Main camera in SGP, and also opened up PHD2 that was defined to connect to STi.
All went well thereafter. Hope this helps anyone else who has two independent SBIG cameras (without an internal guider chip).