I have a newly acquired boat and i need to replace the sending unit in the fuel tank, the previous owner says its about a 45 gallon tank. My question is how do i tell what style or size sending unit i need ?? the old one had a cork float with a cheap gauge on top of the sender itself..i would like to upgrade to one where i can put a gauge in the dash, but i dont know what kind to get, if it helps the tank is about 10" deep