How to program a Singles<->Doubles Sort?

[Goldenwind]

Hey guys.
I'm working with the base ITG2 theme (Groove 2.4) on a fresh installation of StepMania 3.95.

I'm trying to edit the Sort List to include switching between Singles and Doubles. I got it half-working, but there are bugs. Please note this theme is being designed for arcade, so extra restrictions apply.

What I have now: (In theme's metrics.ini)

[MusicWheel]
...
...
ModeMenuChoiceNames=Singles,Doubles,Group,Title,Bpm,Popularity,TopGrade,Artist,EasyMeter,MediumMeter,HardMeter,ExpertMeter,Dance,Battle
ChoiceGroup=name,SORT - Version;sort,Group
ChoiceTitle=name,SORT - Title;sort,Title
ChoiceBpm=name,SORT - BPM;sort,BPM
ChoicePopularity=name,SORT - Popularity;sort,Popularity
ChoiceTopGrade=name,SORT - Top Grade;sort,TopGrade
ChoiceArtist=name,SORT - Artist;sort,Artist
ChoiceGenre=name,SORT - Genre;sort,Genre
ChoiceEasyMeter=name,SORT - Easy Meter;sort,EasyMeter
ChoiceMediumMeter=name,SORT - Medium Meter;sort,MediumMeter
ChoiceHardMeter=name,SORT - Hard Meter;sort,HardMeter
ChoiceExpertMeter=name,SORT - Expert Meter;sort,ChallengeMeter
ChoiceDance=name,MODE - Dance;PlayMode,regular
ChoiceBattle=name,MODE - Battle;PlayMode,rave
ChoiceDoubles=name,STYLE - Doubles;Style,double;Screen,ScreenSelectMusic
ChoiceSingles=name,STYLE - Singles;Style,single;Screen,ScreenSelectMusic

What this does is set the Style (Singles, Versus, Doubles, etc), and then reload the music screen.

Problems with this:
- If I don't reset the music screen, the song list doesn't change. This means that only Singles songs are shown. Songs with Singles charts but no Doubles come up blank. Songs that are Doubles-only don't show. Songs with both are fine.
- If I reset the music screen, the menu timer is reset. This could be used as an exploit to get more free time.
- If I direct them to the "Choose your style!" screen, Singles is grayed out, and the menu timer is still reset
- Resetting or not, it actually works for Singles -> Doubles. However, I can't go back the other way; while on Doubles mode, "STYLE - Singles" is not shown (However is shown while in Singles)

(Note: These arcade machines have Doubles for 1 credit, hence switching between them would not be an exploit.)