When I clean the fowling out of my sidelocks I use pure alcohol. Nothing else. I run an alcohol patch before loading the first time to get any oils out of the barrel, then a dry one.
For fowling, the damp alcohol patch will still bring up the fowling and it will dry by itself in the barrel. I then run a dry one or even two down the barrel to make sure, and they are used as the next fowling patch. I swab depending on how the barrel feels. If the roundball are loading fine without problems and the accuracy is still good, then I do not swab.
Fowling shots are not always necessary. You will have to experiment with the rifle to see if they really make a difference. When shooting some sabot loads the fowling shot seems to be a bigger concern, but I seldom if ever fowl with the sidelocks.
Your rifle has a 1:48 twist and will shoot the roundball just fine. A friend has the same rifle and he shoots 90 grains of Goex FFg and a .530 hornady ball and .018 patch. His accuracy is exceptional.
If you want to try some concials,
Black Jack Hill's sells them very reasonable. You can get some from him and you do not have to worry about spending a lot of money to try them. If they work for you, like they did me, then I bought the molds and cast my own.....