You are in good hands if you contact the Ringstedt radio museum!
I know them very well from visiting them several times by the old mill.
They have more beautiful stuff in the cellar of the school.
But as I said before, count on that these modofications were a solution
to bring back life into the TV set!
I like to say it with easy words, a higher deflection angle (rising from
70° > 90° > 110°) askes more power in the deflection stages.
That means stronger valves, too.
It doesn`t make big sense if you drive a TV receiver with a 17" or 21" CRT.
There are mostly no changes in the schematics, but if you change the angle
you have some changes.
The modern line transformer could be an official interchange part!
This happens offen, when the old stuff was not more available!
Sometimes the interchange part has to be mounted with some changes
in the schematic, who knows if that is the case with your set!
Regards,
German Dalek