My name is***** and I will try to answer your questions today. It sounds like you have your kitty on the correct medications and dosages.
Before deciding on if your kitty is responding completely to the therapies, I would wait at least one month to allow for the fortekor and vetmedin to work by improving heart function and reducing blood pressure. I also would be very hesitant to change the diuretic dose without consulting your regular vet first, as you can have rebound fluid build up if you stop this medication abruptly.
The drugs may also never be able to remove all of the fluid from around the lungs (pleural fluid) as this is a very stubborn place to work with. Our goal when treating HCM is to make the kitty as comfortable as possible and have as normal breathing and heart function as possible. A little bit of pleural effusion, while not normal, is acceptable if the kitty is breathing normally.
A respiratory rate of 30 breaths per minute is well within normal for a cat. With heart disease I would even accept an intermittent rate of 60 breaths per minute (sustained for more than 2 hours, though, is a problem). You also want to look at the character of the breathing- if his abdomen sucks in when he inhales (vs just gentle rising of his chest), or if he is sitting with his head/chin extended, that indicates labored breathing and this is an emergency. Open mouth breathing is VERY bad in cats and he needs to be seen as soon as possible.
Does this help? Do you have any other questions?