@vvk1 @Lowday20298 Thank you for your advices, but I have strong personal bias against Butterfly and I am not going to buy a Dignics, Tenergy, Glayzer, or Rozena.
I am happy to use softer rubbers. I think the Sieger PK50 is 50d, and is manageable for me; I am planning to stick with tacky/hybrid...