I have been looking at snap-off via pins to solder onto the pads BEFORE the board is dropped over them. The pin tips then protrude through the memory board. This would then be a straightforward matter of soldering.

However, there is the issue of clearance between the case and pin tips to address. WIP.

I am becoming more convinced that the RAS connectivity failures observed are due to the DIP switches not having good connectivity after they were soldered on: as Patrick observes, I suspect you need to snap the switches back and forth a few times to clean them then test for continuity/lack of in both positions to ensure they are OK.