I'm pretty sure you're doing a crit build. What is your starting SPECIAL? Did you factor in your Agility and Luck (which are most important, IMO... seconded by Endurance) pre-implants to max them out to 10? Otherwise you would need to have some perk points in Intense Training. And just as a heads up, some of the REALLY fun Guns like the AMR requires 8 Strength. And at some point, you might find yourself wanting to switch your light load out and put on Power Armor and use Miniguns or LMGs instead (I've been there), so you might think to factor that in as well.
I find a 5 Strength to start is decent. 1 point with implants, 2 with OWB completed, another one with LR completed. Came out to 9, put on Power Armor and you're good to go! I like to start with 9 Agility and 9 Luck for such build as well. You can scale down on Intelligence (5 would be OK) because you're not spreading out too much. I would just set Charisma to 1 because what's the use, right?
And this is just for fun: I find that having Chemist (double chems duration) and completing Aba Yaga Honeymoon to get the Turbo recipe can be useful for REALLY bad close-quarter situations when you need to charge in/backpedaling while guns blazing (Think... multiple Deathclaws at close quarter. RAWR!!). Also, double Stealth Boys duration is always fun. There are also two Implants GRX perks you can get, but real Turbos works better, but just FYI.
I can understand your choice on picking Grunt, just as back up because Medicine Stick is not always reliable. But think of it this way: Grunt increase massive damage for grenades AND grenade launchers, while Cowboy increase damage for Dynamites. I would have gone with an Explosive build as well. And with Honest Hearts, you can make unlimited Nuka Cola, and with Nuclear Chemist you can make unlimited Nuka Grenades!
And lastly, I think you can do without these perks: Confirmed Bachelor and Jury Rigging. Honestly, by the time you're level 25, if you were a diligent scavenger you would be able to make TONS of Weapon Repair Kits, so Jury Rigging is totally a waste. And Medicine Stick is usually WAY overkill, so IMO picking CB is also a waste.