New instrument request

I set a lot of early music and I'd like to get an instrument added - a 6 string bass viol. Although a 7 string Viola da Gamba option exists, and can be adjusted, it is a little tedious having to modify the playing ranges to remove the bottom string whenever I want Musescore to indicate notes outside the playable range. I'd rather be able to select the 6-string bass viol as an instrument in it's own right separate from the 7 string viola da gamba. I had it set up as a separate instrument in earlier versions but that option no longer seems to be available in Musescore 4 and I see "removed as duplicate" where it appeared in the instruments.xml.