[Grammar] Comparative and superlative: longer or longest

[Fullblooded]

I wrote this:
"I measured them up: one is 44 inches, the other 40. The good lenght for this style is obviouly the longer one. 40 is too short and it shows!"

I wrote "longer", because 44 is "more long" than 40. But, in the same time, in this situation, it is the longest of them all (there are only two things or two lenghts to compare). I guess I could have written correctly: "The good lenght for this style is obviouly the longest"; a superlative can be used as a noun.
But, still, I'm not sure. So, to get to the point, should I have written:

- The good lenght for this style is obviouly the longer one.
- The good lenght for this style is obviouly the longest one.
- The good lenght for this style is obviouly the longest.
- The good lenght for this style is obviouly the longer.
- All of the above.
- None of the above.

 

[MikeNewYork]

I would use the comparative "longer".

 

[Fullblooded]

I would use the comparative "longer".

So "The good lenght for this style is obviouly the longer one".
or just "The good lenght for this style is obviouly the longer"?

 

[MikeNewYork]

I would go with the first. But you misspelled "length" in both.