In a Sterophile review of an earlier version of the ZOTL40 (push/pull) amp the reviewer mated it with Magnepan .7.
Looks like the newer version (ZOTL40 REFERENCE+) is $1K more @ ($6,800).
Interesting that you were able to drive the 1.7's with the 1-watt power section of the Microzotl 2.
I had wondered if it would work with my vintage wide range single drivers and it looks as if it would with my 8 ohm Elac S517's and 16 ohm Stephens Trusonic 80FR's.
You might check out the inexpensive SS Van Alstine power amp that he decribes as being single ended, or an "upgraded" DNA amp (used) if you can find one.