Opened TE4 slits again to +/-10mm.

Then we tried different scrapers:
in south arc outside: E02DS3HG, cuts at ~ -25mm, at -15mm gone, leave at -35mm.

on straight section: EEXDS2HA cuts at ~ -25mm, leave at -25mm.

EEXDS1HA, closing it to -25mm revealed a double peak structure with distance just like the wanted isomer (-2.2MHz at h=211).
But it is present on all intense peaks at the same distance, so it must be an artefact of a strange isochronicity curve.
Closing it to -15mm even had only the smaller lower frequency line survive.
But then it must be also possible to have only the stronger line. leave at -25mm

This worked with scraper in north arc E01DS_H which can cut from both sides.
The insie can ve iused to cut the lower Brho, 
at -50mm still two peaks, at -45mm left peak almost gone, -40mm left peak gone but right still intense, leave at -40mm.

-> Lower Brho seems to be clearly related to lower frequency, higher Brho side is not so clearly related to frequency.

Measure in this setting, nice void at wanted frequency. But no isomers appear so far.