Welcome from Northern AZ.
I too shoot left handed (I am right handed but left eyed). I have NO trouble shooting my right hand flintlocks left handed. You just gotta train yourself to ignore all the excitement in front of your face before the boom. Follow through. Should be just fine. Get the flintlock first, become real good with it and a caplock will be no problem! BTW a properly tuned flinter is nigh on the same speed of ignition, just takes a bit more load development, which kind a chew to have in yer mouth, powder tilted, rounded, dimpled or flat in the pan etc. Each gun is different.
Have FUN!