Apologies for the delay and thanks to all who have replied. Happily I have traced a source of the original "Gleitplaettchen" material and have ordered same. Thus, the conundrum of viable alternatives to replace it has been avoided. I'm still pondering the differences between adjusting the rail side play of a Rolleicord and Rolleiflex. I suppose the solution will become more apparent after installation and adjustment of the new Gleitplaettchen and following this the relavant clearances of the rails and carriage will be more accurately measured. Best, Brett