No problem! Please let us know how this ends up working for you, and if you have any rules questions or feedback, we'd love to hear it.
Update: So, this is a very reliable build but definitely not the star of the show. If you like playing a support damage role then this is cool but you need to expand a bit into other avenues or it can feel kinda stale. You're not making the big the plays and leveling a map but you are consistently softening up targets for others. I probably needed to build more utility into it. Also, i don't believe this is in the PDF but when determining adjacency for eusocial, we made sure to decide the exact hex my size 1 was magclamped onto size 3 friend so others knew where to stand to use my abilities (e.g. am I on his back his right side/left side, etc.). Otherwise, mainly in tight maps, it feels too overpowered if I'm just adjacent to everyone my partner is adjacent to via handwaving that I shifted outside of my turn.
"Also, i don't believe this is in the PDF but when determining adjacency for eusocial, we made sure to decide the exact hex my size 1 was magclamped onto size 3 friend so others knew where to stand to use my abilities"
RAW/RAI, that's not necessary because a Rider occupies the same spaces as their Host, though yes it's very funky narratively. The wording is borrowed from how effects such as Symbiosis or Mule Harness are described. It's totally fine to House Rule Attached to work the way you've described, though (I presume Mule Harness/Symbiosis are worded the way they are for the purposes of being one less thing to track or book-keep for most tables). Regardless, always fun to see people playing with the stuff we've made.