I love squid and octopus! Up in Prince William Sound in Alaska we used to catch the bigger ones, 15-20 inches and bigger, real meaty. I clean them, then par boil them. Just long enough that the skin is very easy to rub off. Then I cut the body into inch sized cubes and marinade them.
Olive oil, garlic, chopped onions and celery, tomatoes, Italian seasoning, then a mixture of apple cider vinegar, Worcestershire sauce, and lemon juice. Then I chop up some oranges and limes and toss them in. Let it soak over night and yummmmm! Do the same with octopus.
I never measure anything, just throw in what ever amount it looks like it needs and finish it off by taste.