R.D.,
Then do not tell me how authentic your unit is. You spend hundreds of the right muskets, the right uniforms etc. as most units have standard for these - and then care nothing of the flag??????
There are some exceptions to this and those units try very hard to get it right. Some events even have flag standards - I know because I have consulted for them.
I do not know where you are located but would you really want to use the wrong flag at an event where that type of flag never flew?
Of course there are some wrong Federal flags in use - and those cost much more than CS flags typically - but I see FAR fewer wrong Union flags on fields and in pictures than CS flags. It is not even close.
Greg Biggs