There are three main classes of beam ship in my opinion:
Kiters: all the emphasis is on having a range where they can do damage and the enemy effectively can't. Versus the AI, you can run them out of missiles, and then send these in as light cavalry to mop up. Players can reserve missiles for point blank engagements.
Sluggers: Designed to survive to close, and then do far more dps at their preferred range bracket than the enemy. It is a concept that means that anytime you engage in combat, you are expecting to take damage, no matter how much you outclass the enemy
Point defense. These beam ships are not necessarily all that fast. They are as fast as the fleet component they are assigned to. Unlike sluggers, they don't need (much) armor because the only thing that will engage them is missiles, which they expect to shoot down.
Slugger fleet concepts assume that tech inferiority can be made up for with brute mass and numbers.
Long ranged rail guns is unusual. I like railgun fighters for PD for my fast strike force, while my long guns role is penetration at the longest range possible. I suppose if the goal is to be able to batter down shielded targets at range, it works.
There is a bit of a mismatch in your fire controls and ship speed, but you don't have much fire control on tracking speed, so that isn't a major issue.
The Sentinel... I would replace it with a long endurance carrier and put all those specialized weapons on fighters embarked on it. That way, you have a ship that can stand on station for long periods of time while also having the option for its parasite craft to have enough speed to close.