Hi
@Gumba How exciting. .We (my husband and I) are planning / hoping to walk Le Puy to SdeC (and on to Finisterre and Muxia) later this year.
I’ve walked the Frances in October 2011 and April 2013 and the Le Puy in April 2014. I am not directly answering your question about the pros and cons of various seasons - both were wonderful - but I can give our reasons for our timing later this year. We’ve sort of worked backwards from when we want to be on the Frances.
We both want to walk the Frances again - having avoided it for the past 10 years and opted for less crowded routes. We think November on the Frances would feel comfortable for us in terms of numbers. We plan to give ourselves around two months plus a bit! So, we expect we will begin from Le Puy in the last week of September (to allow for Cele Variant) so we can get to SJPP before end of October in the hope that we can walk the Napoleon Route again. From Ponferrada, we may take thé Invierno.
So I guess for us the timing has largely worked around when we want to be on the Frances, as well as some other commitments we have in December.
Someone else may come along who can more directly answer your question.
Bon chemin, Buen camino