Mellotronists

Hi all,
in the process of cleaning up my keyboard and pinch rollers, I've 
noticed that on some of the keys, both screws that hold the pinch roller 
assembly to the underside of the key have washers placed on them, while 
on other keys, only the screw nearest the pinch roller has a washer on 
it.  Should all the screws used to attach the pinch roller have washers?

Thanks,

john

PS - I've also lost some of the felt that cushions the adjustment screws 
for pinch roller and pressure pad tension.  Can I use any kind of felt 
to replace this or does it have to be something special?  If so, what 
should I get?