At those temps it should be fine. As i was getting into the 60's n 70's before, it did warp the plastic around the inlet to the pump and prevented water sucking in.
So this is my second and is working ok.
I run two cables (red/live and black/negative) from the battery to the switch. Allowing me to put the switch where i wish it to go. The switch was just a couple of quid from asda and is very easy to connect.
The pump comes with three wires as its a boat bilge float, but i onlybuse the positive (live) wire and the negative wire which connects to the corresponding connections in the switch. It is very easy to do, you shouldnt have any problems in doing so.
From my vid on my van set up showing the pump, i have drilled another small hole allowing the hose to fit. But you may wish to use the lid of the tank perhaps, or some other means.
At the other end of the hose im thinking of getting a petrol type gun/trigger. This is for when i turn the pump off, gravity feed takes over and currently i have to lift the end of the hose higher than the tank to stop the flow. Whereas a trigger will stop the flow once the pump is turned off.