On Sunday, December 10, 2017 at 3:48:23 AM UTC-5, GS wrote:
make sense to buy two transformers.

There was an old patent using two neon sign type transformers back to back.
The problem with isos, you get higher voltage with no load than normal, and
droop 10-20% with load..

Properly designed Isos are vastly over-sized for the rated load. Which is why a good isolation transformer is not cheap, and a cheap isolation transformer is not good. Can't have both - new, anyway.

The Iso in my Heath is rated at 4A, fused at 3A, weighs around 10 pounds and does not sag. Some of the hospital-grades units I have worked with in the past were heavy enough to be a major PITA to lift or move, and rated in the 8 - 10 A region.

Peter Wieck
Melrose Park, PA