I've tried the transformer and for testing purposes charged him with 20W. At this low load the transformer already achieved an efficiency of over 87%, if I have not miscalculated. Normally, switching power supplies achieve at low load is not their full efficiency, therefore this value is more than I expected.
The quiescent current consumption without load is less than 0.2W and is thus very good.
Exposure to the full 60W I have not done but I expect at good values actually no nasty surprises.
