Hi Mosaic,
You would be sailing a bit close to the wind with an IRF5305 switching 10 Amps.
The IRF5305 RDss is 60mR at 25 Deg C junction temperature. Add a factor of 1.5 for the actual junction temperature and you get, 1.5 * 60mR= 90mR.
At 10A ID that would give a voltage drop of 900mV and a power dissipation of 9W.
The other thing about the IRF5305 is that its thermal resistance, junction to case, is 1.5 Deg/C/W which means that you would need a sizeable heat sink.
Also the IRF5305 needs about 10V gate drive.
The IRF5305 is a nice PMOSFET and is widely used but, for your application, I would suggest one of the newer PMOSFETs with the following characteristics:
RDss at 25 Deg C: 6mR Max
Thermal resistance Junction to case 0.5 Deg/C/W Max
That would give an operating voltage drop at 10A of, 10A * 1.5 * 6mR= 90mV and a dissipation of 900mW so, depending on the temperature in your equipment, a heatsink would probably not be required.
If you would like to change MOSFET type but do not want to search for a suitable PMOSFET I can give you a suggestion.
spec
PS: If you are using pulse width modulation a few other issues arise