Hi Nick,
I think you may have problems if the midi side of things is the same on the T2 as my psr1500.
There doesn't seem to be a way of setting individual style tracks to use either the internal sounds or set it to play external soundsource. Not sure how you'd mute the internal drum sounds.
ie sd2 midied to psr, I have following options
SD2 plays all style parts : PSR plays Melody & Left Hand parts.

Option 2 PSR plays all style parts, SD2 plays melody & left hand parts but only the sounds on the main gm bank.

Option 3 SD2 plays all the style parts melody etc.

Also the internal styles can't be used. Yamaha drum mapping is not gm standard.
The bank & program changes in the internal styles could bring up incorrect sounds in a connected module.

I only tried using this setup with user styles. In the end I found it easier to just keep useing OMB software with the module instead.

best wishes
Rikki