Nice squid pic! Ditto on the proportions of Steve's calimaris, spot on.
Stripers bite the head of any fly. You could tie a 12" long fly with a 1" long hook at the head and the fish will be on when you set the hook.
Like you I am pretty familiar with flyfishing for ocean coho (since the mid-80's) and agree completely that the hook needs to be in the mid-to-rear half of the fly for consistent hookups because of the way they hit the flanks of the prey.
Here is a similar squid pattern I posted a few years ago in the archives. It uses a tube fly tube instead of the stiff nylon. The pic is low res but you can see the big SW hook at the head of the squid, maybe 1/6 - 1/8 the length of the fly. There are a few variations in the image including one that is veiled over the body ironically as Steve does, it's a great effect.
The fish still get hooked with these short hooks even though these squid flies are 5-6 inches long.
I am now developing a series of VERY large flies to cast on 600+ grain heads which feel comfortable to cast all day with the Atlantis Surf-tamer, including a large squid. Should be 'deployed' by the fall migration.
Steve, I will definitely have some of your squid flies tied to about 6" in this selection, thanks for posting!