I just replaced the NVRAM battery on my SS5 using one of these:
http://www.glitchwrks.com/2017/08/01/gw-48t02-1More expensive than a taped on battery holder, but it looks way better. He sells them on ebay for $10 plus shipping, but also has the board layout linked on his site if you want to build your own.
Many thanks for finding this, sir! I'll be needing to do this at some point down the line, though my main SS20 and SS5 machines are still ticking away with their original NVRAM batteries 20+ years later...
I love using NS 3.3 on my Sparcstation 5 with the FX graphics board...