I think the sending unit will be about the same size, however it will be flush with the tank so it will be easier to use the fish tool thru it. Removal of the fuel sending unit might help you see the object if it (sending unit) isn't hidden back under some sheet metal. If it is located where you can remove it without removing the tank, then you could put a high intensity flash light in the fueling nozzle and fish thru the other or vice versa.
However, it something got into the tank, it went in the fuel nozzle so it should come out. Get one of the little steel finger tools from just about any auto parts store or Harbor Freight. That should grip any small item