

They aren't as tough as pure bricks, but are tougher than energy blasters/martial artists. They're dangerous on offense but easy to hit. Likewise they should have a wide range of sensory abilities to detect Invisible characters and the like. Rely on pseudo-real world attacks instead of Star Trek colored lights (i.e., a gas attack could theoretically affect most Desolid characters, as they still need to breath - so use that instead of some ghostbusters energy beam). Sentinels are expected to fight all different sorts of mutants. Give them a range of attacks that would be useful against different character types. You don't have to worry about building them as Automatons, just do them as normal characters and give them a Disadvantage "destroyed when reduced to 0 Stun".

My preferred version is that a lone Sentinel is more powerful than an individual hero, but their tactics are fairly simple and they don't travel in as large a group as the PCs do.

So the first step is to decide which of these you want to emulate. Sometimes the X-Men would have to team up to defeat a single Sentinel, sometimes each X-Man could take out one or more on their own.
#MARVEL SENTINEL HERO PC#
Build your Sentinels to the desired power level compared to your PC group. I'd suggest something like this for general guidelines:
