MIMF

If I remember right the string spacing is (low to high) 4 mm, 3.5 mm, 2.5 mm and 2.5 mm. the spacing between the pairs is (low to high) 10 mm, 9.5 mm and 9 mm.

Thanks, Ron - the pic is helpful. I guess the saddle has slots, unlike a guitar, to set the string spacing, as the distal wound strings seem to hit it at a slight angle to clear the proximal pin heads. Also, why is the compensation like that (I've seen it in other pics also, and on mandolins) as opposed to compensation based on string diameter as on a guitar? I'm just planning on cutting the saddle slot with 1/8" compensation.

My string spacing between pairs is planned about 1/2mm wider than yours yours - my scale length is 620mm.

Thanks for the book recommendation, though it's a little late, since the instrument is built except for the finish and the bridge. I just used a picture on the internet and scaled it up. I used Cumpiano and Natelson for most of the construction process. I've never seen or heard one of these instruments - I'm just building it for educational purposes.

Sorry to be a bother with my ignorant questions.

Peter,
No bother
I have slotted the saddle in the past but this one seems ok without. The pins I am using now come from Gurian and the head is a bit smaller than I've used in the past, where I've had to file the side of the pin for string clearance.
The compensation is what is recommended by MacDonald and it seems to work very well. The saddle is about 3/16 in. + a bit and it is not angled but it is compensated about 3 mm.

Ron, I saw this a while ago, but didn't have time to commented - it is really a beautiful instrument.
Bravo!