Reaching out to knowledgeable members as to which is the best gland packing to replace on my cruiser. I have removed the existing which has been in service for 21 years - (6 rings) which looks like PTFE which has gone quite hard. Has anyone had experience of PTFE and silicone, (seems to be a new kid on the block) compared to PTFE flax Sturntite or Graphite cotton. My stern gland is water lubricated/cooled - not greased. BTW, the stuffing gland is bronze with 2 clamping/tightening bolts. Appreciate any guidance on the wear, heating and longevity.