It sounds like you’ve done your homework.
From the weights of your boats it sounds like they might be lighter composites (read FRAGILE AND EASY TO DAMAGE!). How much do you trust the airlines and all the gorillas working in baggage with your boat?
Check out this video about a very nice and expensive composite damaged in transit/shipping:
What is your ability to repair your boat when over there, can you plan B it in some way? Another consideration is where will you be staying as well. Europe is cramped compared to USA and the South is more cramped than the North in general. You will need a certain size accomodation if you’re planning on staying in a hotel to store your boat. Many hostels and even “above average” (not the cheap ones) hotels won’t have enough room for you to store your boat. Stairways are very narrow and tiny and cramped in the old buildings you are likely to be sleeping in. I don’t see you being able to fit even a foldable kayak in an elevator and many stairways. Doorways are also likely to be smaller than you’re used to in all but the most modern hotels. Leaving a kayak unattended in a hotel is iffy, private property respect in Europe << USA and it’s worse in the South (like Spain or Italy) which are also full of Gypsies, illegal aliens etc. Also unemployment is very high, as is the petty crime/petty theft rate, watch your property!
Food in Andalusia (South Spain) is very good, not as good as Italy if you can compare. Spain has similar gastronomy and selection of menu items but the better known Italians do it better, more vibrant, more flair, more fresh, more quality, more flavor more interesting. Still the Tappas are quite good and probably the best way to try a lot of different things cheaply. Ask for “PINCHOS” (many little snacks, as in lots of different “tastes”). Again Spain is beautiful but there’s a dullness, a seriousness and a sadness and a spotlessness/cleanliness in Spain that you don’t see in Italy, kind of like the “GERMANS OF THE SOUTH”. It’s mild but worth noting. Spain looks more “poor” but it is cleaner, in many cases more uniform vs Italy which is wealthier, more lively, more shiny but at the same time dirtier, more chaotic and more dilapidated. Spain has some of the best roads in all of Europe. Cost of things in Spain is lower than most USA, it’s cheap over there, average wage is $12,000 Euro. Don’t forget to check out Granada and the Alhambra, it’s a must see. Probably the biggest must see in all of Spain and one of the top “must see” sites in Europe. Going out of your way to see it and spending the whole day is 1,000% worth it.
Beware the currents in the strait of Gibraltar, almost all the time go towards the med due to salinity differences Atlantic/Med so starting Atlantic in the East and going East towards the Med is the easiest, and probably only way to navigate. Also the channel is alive with shipping so keep a watchful eye on ships staying close to shore.