Here's how I sculpt a tendon:
And static shots from the completed spine in the video.
The inner spine is [almost] complete though.
It's not perfect by any stretch but after the gloss and Tamiya Clear Red X-27 it doesn't have to be.
My next stumbling block is how it interfaces with the ground. I was going to use some of the wood chips I used on my 'ground-bursting' Trygon but I still need to add some lava stones to look like alien growths. It's a fair bit of work and not without challenges, hence why it has almost caused my renewed efforts to stall...
The emitter node also needs adding to the pen tube so I can then add veins and whatnot before I then try and sculpt the inside of the battlements.
The black mark is for one extra tendon that needs to be sculpted in place. I've got some concept elements for the battlements - which is an odd situation as in 8th edition the building rules are far more streamlined now with less room for interpretation. It's still possible to position models in the standard Imperial VSG but nowadays this would probably be considered modelling for advantage.
I mean I did specifically build it to fit a brood of Devgaunts in but that was perfectly legitimate with the prescribed rules in 7th. Anyway, I doubt it's ever going to a tournament so it's not really an issue.
Anyway, not sure when/if I'll do some more on this, Dreadtober is my focus but I will have some extra hobby time between writing this and it's scheduled publish date, so I might have one update soonish or none for six months to two years...😂