I treated myself to a Lyra Etna last month and can only describe it as “remarkable”!
The recommended loading from the importers is to “to be determined by ear”. I have settled on the 1000R plug at the rear of the Superline as the best to use in my system. The 500R is an alternative if the 1000R does not do the job.
A further refinement would be a pair of AirPlugs which I have on order from my dealer. Does anyone have experience of them? Difficult to see how much further you can go in getting quality sound out of the good old LP.