Alright, the rolls gave us some spare leeway to play with in the requirements, so -
[X] [Body Size] Balanced Hull
[X] [Body Size] Snub-Nosed Hull
Either of these is fine, none of the other options provide a decent benefit to penalty ratio.
[X] [Body Style] Reinforced Hull
Reinforced Hull provides some outrageously good and comprehensive defensive benefits for a small ProdCost and no TechCost, so that's going in the selection
[X] [Limb Style] Crouched Dorsal Legs
Similar thing - that is some ludicrous defensive and productive benefits for its cost.
[X] [Actuators] Flexible Actuator Design
And this eliminates most of the Agility loss. So final score comes out to this;
[+2] Build & Repair Speeds
[+1] Reduced Height
[+3] Armour Plating
[+1] Skeletal Durability
[+3] Skeletal Stability
[+1] Pilot Protection
[+2] Component Protection
[+1] Actuator Precision
[-1] Production Cost
[-1] Technology Cost
[-2] Limb Drive Speed
So for a minor loss in ProdCost + TechCost + DriSpeed, we get
Significantly improved Building and Repair Speed,
MASSIVELY improved across the board durability through a combination of increased armor and reduced chassis size
Mildly improved agility
And perhaps most importantly, more Skeletal Stability which will both keep us going good in rough terrain, and allow us to mount bigger weapons and more armor.
But Gorilla tactics is pretty much the only option for a defensive mech we have at this point, with what options we have already picked. Harrass and keep enemy mechs pinned down from long range. Evade and make it expensive for everything they take. We do not have the bulk for extreme range artillery or just out armor an enemy to hold a line.
This Mech is in the 55-ton range. A standard 5-inch Artillery Gun in the real world (like the kind you'd mount on a naval destroyer) weighs, with ammunition, a total of 24 tons or so. Depending on how much it actually weighs after this with tech levels and whatnot, we can absolutely do decent artillery.
Plus, assuming we vote to keep our Limb Agility and Skeletal Stability medium-rate or above, this will be an excellent rough-terrain and urban chassis. And that doesn't account for the possibilities of hefty defenses.