I own and shoot two TC Patriots. The factory recommends loads far less than you are thinking about using. Anything more than 25-30 grains and you are courting a possible cracked stock. The pistol has an unfair reputation for cracked stocks. I know several Patriot shooters, myself included that have never had any cracked or broken stocks, or any complaint about the pistol at all.
The pistol is a target gun. I shoot 18-24 gr FFFG blackpowder only with a patched round ball, .440 cal. It is a tack driver if I do my part.
You reach a point of diminishing returns with more powder in the barrel. The charge is still burning after the ball has already left the barrel. So, it is a waste of powder.
If I recall correctly, the rate of twist in the barrel is 1" in 22".
I did meet a guy who blew up a Patriot clone. He wanted to see how much it would take. He stretched the pistol beyond it's capacity. Bad mistake... The stock let go, the barrel let go and so did every other piece of furniture on the gun, along with a thumb. He spent a lot of time in surgery being reconstructed.
A lot of damaged Patriot stocks are caused by mis-use by the owners. They either over tighten the lock bolt, cracking the stock, or let the heel end of the stock rest on a hard surface during the loading process. This causes the stock to crack and break also. And there are those who over charge the pistol too many times. You might get away with an over charge once or twice, but what did the previous owner do, and how many times...
I would strongly advise to just use the pistol for what it was intended for. Round ball and charges under 30 grains.