Is this True? Can you make use of Climbing plus as if it were a deployment skill? Don’t you have to declare move for the Skill to be in effect?
It's not that you are using climbing plus as a deployment skill. Indeed, you could stick any trooper on a wall as long as it's wholly within your DZ. The problem with doing it for non-C+ troops is that they can't do anything once they're up there, not even ARO.
On the top of my head, I'd swear you should place a climbing model with the base "glued" to the wall, so you don't need a wall taller than the S2 of the Speculo AND taller than the size 7 of the Zeta. This would mean, let's say 40mm for the Speculo's height and 55 mm for the S7 TAG, meaning you need a "wall" at least 10cm in height and 56mm in width to totally conceal a Zeta from the enemy and protect it from the Speculo. I think a simple building with a container on top suffices for those measurements (like the ones for MotoTronica/Hefestos/Ariadna, but it's better if you use the Red Lotus/Coldfront ones). Of course, it won't protect against shooting, but an ARM8/BTS6 TAG can survive much better anything that is not a multicritting shooter or a melee Speculo. This also opens a good tactic for the Zeta: if the enemy trusts melee warbands to negate enemy TAGs (like chain rifle Myrmidons), sacrifice cover and stay on the walls higher than S2's reach, so a single warband cannot pin your TAG (specially since a Myrmidon would roll 1d20+4 against the TAG's 14 after applying MA3, and with PH13 and an AP CCW the greek can wound on 50% of the impacts...)
Still hilarious, a gigant killer robot hiding in a tree from a guy with a sword (a very good sword, but a sword after all) like a cat is still hilarious. Spoiler: TAG new meta