Air Tight needs light speakers such as Coinsident that are friendly to OTL amplifiers. It's definitely clipping and OTLs clip very unpleasantly.
You can add integrated Plinius 8200 used for ~1.5k, keep your Air-tight preamp to adjust the level for tonal balance in bi-amplification setup if possible.
Avalons arn't best to be used with tube gear in general and like amps that could work as welding machines. If you look through the posts about Avalon speakers here you may find Tireguy's system with BAT VK500 which he believed is the "key-word" for these speakers.
You can add integrated Plinius 8200 used for ~1.5k, keep your Air-tight preamp to adjust the level for tonal balance in bi-amplification setup if possible.
Avalons arn't best to be used with tube gear in general and like amps that could work as welding machines. If you look through the posts about Avalon speakers here you may find Tireguy's system with BAT VK500 which he believed is the "key-word" for these speakers.