Glissando on 2-lines staff

I would like to have possibility to notate violin on 2-line staff. I’m using a nonstandard technique, so the lines are to show lowest and highest register on given string. It would be easy to do it using an additional percussion instruments (like 2 bongos) and doing “instrument change” but infortunetely there is no possibility to notate glissando between two bongos and I have a lot of glissandos (in fact I’m using this playing technique just for glissandos from lowest to highest register).
I want to notate something like this:

Any ideas?

And the second question. In this example there is divisi just to make difference in bowing. When I’m trying place down/up bow mark below the notes (using the toolbox “placement–below”), it’s appear like in mirror reflection. Is it possible to place playing technique below the notes without this transformation? I mean apart of manually move it in engrave mode.

Thank you.

I don’t think this kind of non-standard notation is practical in Dorico just yet, I’m afraid. Trying to stretch the percussion features this far will require a lot of workarounds. Really you need a “proper” pitched instrument with a non-standard number of staff lines, and until we are able to make it possible to edit instrument definitions directly in the program this is going to be very difficult for you to achieve by other means.

We will definitely make it possible to edit playing techniques so that you can, for example, prevent Dorico from inverting the bowing marks when you change their placement.

Thank you, Daniel, for your response. I appreciate that.