F recorders, sopranino, alto and bass. Are their music scores transposed, like clarinet scores, all fingers on being low C, or are they written in concert pitch, all fingers being low F. If the latter, it is going to make it hard to change from a C instrument to an F one.

The publisher Peters used to offer some music transposed allowing you to use C-fingering on an F instrument. I'm not sure if they still publish those pieces. My suggestion is to learn the F-fingering. You can read any music within range of the instrument.

There are times when the tenor part is written in the bass cleff, but it is mainly in the treble cleff. I had a clarinetist friend that refused to learn f-fingering saying the music should be transposed. He missed out on a lot of great music that way.

Check with magnamusic.com, Tim may know what is available. Magnamusic is the largest recorder music retailer in the US. Tim is the 3rd generation family member running the business. Unfortunately, his mother Madeline, passed away last month after running the business for 40 years.