The BH209 is a good option. It does smoke some, I just bought 2 more containers of it at Cabelas.
The load you mentioned is close to what I load 223 cases in wt with. This is just not a good idea and take a few days to really think about what you are planning to do. Read up on burn rates and pressures produced. I am not saying it can not be done but sooner or later the metal of the barrel will fail as its not designed to take that. Even once may cause stress fatigue and it totally fail using ML powder the next time. Plan on keeping the weapon forever because it would be 100% gross negligence to ever sell it someone else.
You do not want to use IMR4198. Think about this, in my Para-Ord P1245 I load Winchester 231 @4.5gr and pushes a 230gr bullet near 800fps. Pressure is somewhere around 18k.
I am trying very hard to not insult you because I want you to think about this.
If after all this you decide to do it anyway make sure you film it
