Gittern vs. (4c) guitar

[Waling Tiersma]

I've just added a recording of Cantiga no 9 from the Cantigas de Santa Maria to my playlist. We performed it with different instruments, starting with my 4c guitar. I like the sound of the instrument in this kind of setting but realise that the instrument is of a later era.
What are the opinions about using the 4c-guitar as a gittern?
Should I acquire a gittern (i.e. build one...)?
I am not familiar with gitterns and playing practice.
What is a common way tot tune a gittern and is it (always) played with plectrum?

[Timo Peedu]

I have a 3 course gittern (there's a picture of it in my page on lute group). I tune it (from bottom) either c, g, c' or d, g, c'. I play it with plectrum.