You can start several devices by setting "-d 0,1" in your .bat file (0,1 would be OpenCL device indexes which is listed when you start the miner, yours might be different).
The decreasing hash rate is not to worry about, it´s simply a 32bit counter wrapping (reaching it´s maximum value and starts over from 0) it is only visual and won´t affect actual performance.

Well now that I actually helped someone for a change I would like to give some feedback to the developer. Currently if/when the miner lose connection with the pool there are never any attempts to connect back again, it would be awesome to have a reconnect feature so we don´t lose any hash time. I know I'm a lazy bastard asking you to implement this rather than doing it myself but it is probably a quick matter for someone familiar with the code

Also, thanks a lot for your efforts with this miner.