If you go into mysql, e.g.
mysql pluto_main -uroot
you now have access to the database that LinuxMCE uses internally.
If you do an SQL query, e.g.
SELECT * from Style;
You will see all the rows of the style table, corresponding to different "Styles" used by HA Designer to draw lots of things like "text".
Notice that one of the rows, has a description of Clock, this is PK_Style # 27.
If you then do a query of:
SELECT * from StyleVariation WHERE FK_Style = 27;
You'll see the information for style #27. PK_Style becomes FK_Style out of convention, because in the Style table, the Style is a primary key, whilst in the StyleVariation table, it is a Foreign Key (it references another table).
Note the columns in StyleVariation, particularly PixelHeight. This is the value we want to change.
If you then do an explicit query of:
UPDATE StyleVariation SET PixelHeight=600 WHERE FK_Style=27;
You've then changed the Pixel Height variation from 840 to 600.
After this point, you'll need to regenerate the orbiters.