GUEST, vielleuse -

You may have posted here before, but I don't recognize the "nom." If you're new, you may not be aware that some older threads were disordered by a database mishap a few months ago. This thread is one of them.

Older posts in this thread will make much better sense if you click on the "printer friendly" blue link at the top of the thread. In print view the posts will be in order. (but links won't work there, so you'll want to use the "back to thread" button to check here for any that might be interesting).

Your F C F C or F# C# F# C# tunings are quite a bit off the normal G d a' e' tuning for which common mando string sets are sized, and I suspect you may need to create your own sets from individual strings. Several people here have suggested sources for string gauge calculations to suit odd tunings, in other threads; and mandolin cafe once had a "string calculator" up, although I haven't been there for a while.

I doubt that you'll be able to use any typical "mando string set" to get good tone across all the strings with those tunings. You'll need to find a brand of string that's satisfactory, and that's availabe as individual strings of the gauges you need.

John