Luca
shorter would be nice however, minimum-length has no effect since it's not maximum. I can do it with shape however, the idea is to have a function I can use on all the acciaccaturas - and on some it has a weird effect (I find). I can change the ratio -to avoid collision- however as you saw in the first example it tends to look flat and unnatural. These are the reasons I made my own but, again it didn't look nice once other slurs were added. Perhaps I will look at the examples Pierre made for path and draw a really nice natural looking slur.
I am at a lose for now..