Well ... I have to shime in for the tempo thing.
7/8 and 7/4 is not the same thing and won't ever be the same.
7/8 imply seven 8th in one bar while 7/4 imply seven 4th really not the same thing. Also the 7/8 will feel in three while the 7/4 feel binary even if you do a triplet.
Also a 7/8 will have those strong beat : 1 2 3 4 5 6 7
While a 7/4 will have those strong beat : 1 2 3 4 5 6 7
I'm afraid your understanding of this aspect of music is not strictly correct and I'm responding here to prevent people being misled by what you have posted. By the way - "tempo thing"? Not sure what you mean by this. Anyway...
I'd respectfully suggest that you think again about what the bottom number in a time signature actually tells you. The top number tells you how many beats there are in a measure. The bottom number tells you the chosen duration value that has been assigned to each beat, and no more than that, even though people will often try to infer from it information that isn't really there (as is the case with your comment).
A time signature of 7/4 or 7/8 doesn't really tell you anything about where the strong beats are at all, or the "feel" of the rhythm. Anything with seven beats in a bar could be written either way. There is no inherent difference in feel that's due to just the time signature.
(By the way, I think we also need to be more careful about how we use the term "triplet" when talking about musical time - it's most definitely NOT just a collection of any three equal duration notes or any three beats in a bar.)
