Some people have used hard line. Recently owners have been taking advantage of a very easy do it yourself replacement hose sold by vintage air under their trade name and available from Aeroquip in their EZclip system.
It is very noticeably smaller in diameter and very easy to route in tight radiuses.
I noted your current hoses are listed for R12 Freon so I do imagine you will be replacing all of the hoses for the new Sanden and converting to 134a?
this is the hose I used in my recent projects and I was able to add both hoses to the right hand sill area
The current 90° fitting on your evaporator could be replaced with a 180° fitting which combined with the smaller, new hose would likely be a solution to your space encroachment problem
Larry