Need Single instance of FFP with mulltiple .exe's concurrent with installed FF

Getting Firefox is already running. Running installed FF 52.0.2 (32 bit) and Portable 2.0.4.1 as downloaded. AllowMultipleInstances=true and moved to FirefoxPortable.exe dir. Would like to have new tabs opened instead of new window. Many reported problems are looking for multiple instances and not what I am looking for.
Currently use installed Firefox with a local Autoit/iMacros app using imacros://run/?code=... and shellexecute which opens new tabs and not new FF window. Would like to use Firefox Portable in place of the installed Firefox for the local app. Have tried replacing the Shellexec's with RUN statements which is at command line level and still get same results - already running message.

Noticed in about:support that "Profile Folder " entry does open FFPortable profile folder, but the "Profiles" entry about:profiles shows the root directory and local directory associated with the installed Firefox @ c:\users.... roaming .. xxxxxxx.default

Have not installed iMacros addon or any addons to FFP and if FirefoxPortable.exe is selected twice from explorer you get already running, which is for sure. Installed firefox initiated the same way will open a new tab if no blank tab exist, or do no visible action if a blank tab does exist.

Don't know what an .nsi file is, but looks like that is the gate keeper.

?? Can I use Portable FIrefox with multiple calls without invoking another instance? If so would appreciate any suggestions. bitpicker