Tune 0 is the same as "disabled", it's the default setting to keep the best sound quality. To get a smaller file than with 0/disabled you would need to set it to 4 for instance. The setting is used to be able to tune up the dsnd on the module but in this case it would just be to use the side effect from it, producing smaller files (increasing max tune up decreases the dsnd file size)
For the hihat you can also try the setting to reduce the amount of articulations (open levels) in SDSE Options > Zones, Hats, Maximum articulations.
DSound Manager can also be used to remove articulations from an existing dsnd (double click the dsnd to open it, uncheck some zones click save as), or to shorten the length of the samples from existing dsnd files. It can be combined to get smaller files, on the Tune page you can set both a max tune of 4 and a maximum length then click Tune to create a smaller dsnd.
For the hihat you can also try the setting to reduce the amount of articulations (open levels) in SDSE Options > Zones, Hats, Maximum articulations.
DSound Manager can also be used to remove articulations from an existing dsnd (double click the dsnd to open it, uncheck some zones click save as), or to shorten the length of the samples from existing dsnd files. It can be combined to get smaller files, on the Tune page you can set both a max tune of 4 and a maximum length then click Tune to create a smaller dsnd.