This is a question for anyone with experience on 18th century Neopolitan instruments, original or modern copies.
I am working on solo repertoire, some 18th century. Leone, in particular, uses a technique that Neil Gladd refers to as "string-splitting", or fingering a double stop on one course. For example, one plays a d on the top string of A (second course) with,say, the rh middle or third finger, leaving the bottom string of the course open, thereby generating a double stop.
With practice I find string splitting possible at tempo on a modern instrument -- in my case, a Collings -- although difficult (and easier on the A course than on the D course). My question is whether the technique is more (or less) feasible on an 18th century instrument, perhaps because the string spacing at the nut is different from a modern instrument.