Thanks!
The new GPU miner 0.31c is indeed a bit faster in BitTube v4 (CN Heavy variant) than its predecessor. My Radeon RX 580 4GB @stock hashes with 672 H/s now (vs. 655 H/s with the old 0.30c). Settings are:
"gpu_threads_conf" :
[
{ "mode" : "GPU", "worksize" : 8, "alpha" : 64, "beta" : 8, "gamma" : 4, "delta" : 4, "epsilon" : 4, "zeta":4, "index" : 0, "multi_hash":432 },
{ "mode" : "GPU", "worksize" : 8, "alpha" : 64, "beta" : 8, "gamma" : 4, "delta" : 4, "epsilon" : 4, "zeta":4, "index" : 0, "multi_hash":432 },
],
Higher intensity is not possible because a FullHD display is connected.