DK Design MK II as a preamp with Druid speakers?

I am shopping for a new amp and considering both intergrated and separates. I am currently using a DK Design MK II which is an integrated hybrid with a tubed preamp and a SS 150 WPC amp. I only need about 5 WPC.

I am considering using the preamp portion of the DK for some of my listening tests. It has preamp output jacks. I guess my question is whether the preamp in the DK is a reasonably good standalone preamp or if I should just buy a preamp for my tests. If I buy a preamp, I am considering a Modwright or a MiniMax. I just want to try sepaerates without having to purchase a preamp until I get some idea of the benefits.

I am running high efficiency speakers (ZU Druids at 101DB) and looking at these amps (some of which are integrated):

First Watt F1
Red Wine 30.2
Yamamoto A-O8S
Manley Stingray

Any ideas to add to my list would be appreciated. I want to stay around $2,000 used.

Thanks for your comments and suggestions