This is a build based around the more group utility oriented Gunlancer build.
You'll notice it's only 216 points. That is on purpose. I've only put 6 of the 8 available skills in this, as well as only bringing the skills I listed to the minimum I feel they should be at on the Tripod.
This is built with the assumption that you're going Combat Readiness over Lone Knight and want to focus on the Blue Build.
The other 2 skills are entirely up to you. Personally I like: Sharp Gunlance as it is a good short cooldown skill with some moderate stagger. If you're being swarmed it opens up long enough to turn on your shield. Shield Bash as it has that small dash forward which is great for positioning mid combat.
Another good option for your final 2 skills is Shield Shock, as it's 2nd tier tripod has Ready Defense which is on command 20%+ damage reduction.
For engravings you will want to look for any of these: Barricade, Grudge, Cursed Doll, and Stable State. Barricade is by far top priority because with this build you should have very little downtime on your shields. My second priority is going to be Grudge, as again, your shield uptime should make a healing cut almost a moot point.
For Awakening Skills use whichever you want. Judgement Spear is better for burst DPS. Guardian Shield is better for sustained DPS. This build does best sustained dps, as your shield allows you to reposition less and have more uptime in combat. Guardian Shield just leans into that.
Big thanks to /u/edreamer223 for his guide, which this is mostly based on.