2.90 Vertex slide snap; how to control what axis to snap to?

I was very excited to hear the new implementation of snapping while vertex sliding.

However it seems the new snapping assumes I want the snap axis to be the perpendicular axis of the edge I am sliding on. This is a safe assumption when working in straight edged scenarios but if the two edges I want to join up when sliding will not form a 90 degree angle at the intersection then I cannot use the snap functionality as it is implemented currently.

Please have a look here; https://devtalk.blender.org/uploads/default/original/2X/9/9488b27ee691229bb89a942af1966d9035b3ea6b.jpeg

In this example I have two planes rotated in odd angles. I want to slide the vertices to the proper intersection point so I can weld it up nice and tidy. However since vertex slide snap only allows me to use the perpendicular axis to the edge I am sliding on, vertex slide snap doesnt really help in this situation.

Am I overlooking something?