I've taken into account the information in this gist to add an option to set a run as active in Battle Subway.
When setting some fields to certain values, you can make that the "past streak" fields are "current streak" fields, so that when asking to enter a certain subway you continue from that streak value.
I've also added the "Met NPC" field, set to 1 by the game after meeting the NPC in the Multi Subway once.
Finally, I've added two fields: the first lets you set the current/last subway type used, and the second enables you to set the number of battles won (only used when saving between combats in the subway).
I've not exhaustively tested all of this in BW, but the fields are the right ones (I manually edited the .sav with a hex editor prior to adding it to PKHeX and they work).
I have yet to test it in B2W2 (I'm in the second town).
I've taken into account the information in this gist to add an option to set a run as active in Battle Subway. When setting some fields to certain values, you can make that the "past streak" fields are "current streak" fields, so that when asking to enter a certain subway you continue from that streak value. I've also added the "Met NPC" field, set to 1 by the game after meeting the NPC in the Multi Subway once. Finally, I've added two fields: the first lets you set the current/last subway type used, and the second enables you to set the number of battles won (only used when saving between combats in the subway). I've not exhaustively tested all of this in BW, but the fields are the right ones (I manually edited the .sav with a hex editor prior to adding it to PKHeX and they work). I have yet to test it in B2W2 (I'm in the second town).