Adding a recent acquisition to this post, a J.L William 1 Ohm after it made a journey across Australia, where unfortunately it lost quite a bit of oil, question is, which is better, Paraffin or White Mineral Oil (food grade), as both of these are locally available and to what level should it be refilled.
After opening up to inspect the internals as the readings obtained were not stable, it was noted that winding #2 (from top) has been replaced at some time, noticeable due no varnish and newer looking twine, should varnish be applied considering its already oil soaked, if so, any leads on cleaning.
After the coil unit has been out of the body housing for a couple of days the readings have somewhat stabilised using a 4 wire setup into a calibrated HP34401A.
Any advise appreciated. Thanks, Alan.