If you want literally to make Fast Dial your home page it is easy enough

Go Firefox/Tools/Options/Main

"when firefox starts: select
show my home page

For home page enter
about:blank

If you simply want to have Fast Dial on Firefox bootup

you can enter
When firefox starts:
select
show a blank page.

Firefox will then open in Fast Dial.

With such an arrangement, one can have for example google as one's home page by entering google.com in the home page field.

Fast Dial has worked this way for some time.

In addition if you have the fast dial icon on the toolbar you can click on that to access Fast Dial.

many thanks

chrome://fastdial/content/fastdial.html