Favored KT-88's for Sonic Frontiers amp?

I'd take Chris' advise, even though I've never used those tubes in my 160's. This amp, as least my unmodified one, has high plate voltage and needs rugged tubes. A lot of KT88's aren't up to the task. I've used SED KT88's but didn't like the tone even they didn't fail. I ended up using SED 6550's and if/when I ever retube them I'll be trying the Gold Lions.