I just purchased the 305 with the multisport package. I have a Vision aerobar setup with the Profile design aero bottle. It doesn't seem that I'll have enough room with the bottle and the Garmin between the bars. How have other people dealt with this? (other mounting location?, ditch the bottle?, just wear on the wrist?)
I have my 305 mounted on the stem of my bike. Its a little harder to see (I actually have to make a point of looking down) but that keeps me focused on my ride and not staring at the bike computer as much. Good luck let me know where you end up mounting it.