I know there are a lot of factors that need to be accounted for, but my experience with imaging with small refractors taught me that there can be a significant difference between f/7 ED doublet and f/6 triplet when it comes to RGB imaging.
RGB image taken with 80mm triplet (please excuse crude processing):
https://www.astrobin.com/full/53544/0/
RGB image taken in the topics with 105mm triplet (somehow less crude processing):
https://www.astrobin.com/full/346610/0/
RGB image taken with 102mm ED doublet (developing-level of processing):
https://www.astrobin.com/full/105505/0/
My example of a doublet was much better for narrowband imaging, but there was still an improvement when I swapped to a triplet.