What I find helps is to watch the ATB gauge and listen for when the attack hits and that is when I cue the next attack. It will take time and a lot of practice but you will eventually get it.
The HD version has no stun locking since we do not use the girls.
As far as I know, emulator runs are banned on speedrun.com. This is something that will need to be taken up with the ones who make the rules on the site. Someone else has also asked me about this same issue and told them the same thing. There is nothing I can personally do about that.
All I can say is to keep on practicing on emulator until you can afford the equipment. There is nothing stopping you from practicing.
I would like to be a mod on the Final Fantasy X-2 page. I noticed that it hasn't been updated with the HD and International runs yet. And the page is slightly outdated.