"In my speech: [...] "Infinite" is a single, trochaic or spondaic foot."

The use of the terms trochee and iamb poses a problem.
Strictly speaking, in Latin poetry, each are made up of three morae. The
stressed item lasts two morae and is uttered on a higher tone.

Trochee :
The first syllable is stressed, and corresponds to two morae.
The second syllable is unstressed, and corresponds to the third mora.
The first syllable is unstressed, and corresponds to the first mora.
The second syllable is stressed, and correspond to the last two morae.

For my analysis of English prosody I need to posit that even stressed items
last one mora, not two.
Trochee : one mora stressed + one mora unstressed
Iamb: one mora unstressed + one mora stressed
It is also necessary to consider that there is a completely unstressed foot
in English : |°°| (Should I call it a "dibrach" ?).

Thus <infinite> will correspond to
1) |"°|'(°)| with the unstressed mora of the second foot dangling.
2) |"°|°(°)| ditto.

and <infinitely> to:
1) |"°|°°|
2) |"°|'°|

The clerical pronunciation of <infinite> would correspond to |"°|'°| : ["?In
°fi '°naI].

Of course this analysis of mine is absolutely artifical, and the natural
tendency will be to say that "infinite" is stressed "°°, in other words that
it is dactyl.