Hi el-folie
Quinto Sardo is a nice guy, drop him an email, the SKBow has the zero-relative, I remember I suggested this feature to Quinto, quite some years ago.
The ribbon in the original works like that: when you put your finger on it, the "on" message is generated and buffered as the zero, so as long as you have the first finger on the ribbon that will be the zero; if you put another finger on, the result will be the pitch shift which is 0 +/- the actual position of the second finger, here is why you can do trills; being so there is no glide between the two positions. SKBow has this function as a hardware implementation which obviously should be trimmed with the midi message you've got then.
Of course keep in mind that the ribbon is a completele integrated feature within the CS80 so it reacts also according to the KAS assignment, therefore you can make special effects when using the ribbon together with Sustain 1 or 2, getting different results at that point.
Arturians will be releasing this famous version 2.0; I really hope they will succeed; I'm not the one to tell them where to go, they do have a real CS80 in house so they can do these measurements on their own.
They should implement the KAS logic which is hard to understand; it took me a lot of time , as I'm not a technician or else; once they will implement it , lots of problems and bugs will be taken out as a consequence.
As for the filters: you know, when the HPF is full on the sound disappears because you cut the basses, so why a preset like FUNKY3 does not cancel the sound into the sweep, even with AL at full?
Come on, it's not hard at all.