When I first planned my wet/dry, I wanted to use a siphon too, as it seemed extremely efficient and easy to do cuz that was how I did my water changes. I was pretty stubborn about it too when others told me to just use an overflow. I eventually listened to them and it works great.
I realized that the problem with a siphon is that your water pump would have to match your siphon flow rate exactly or else either your sump will run dry and your pump will fry or your tank will run dry and the siphon will break.
I'm just saying this cuz it seems like you plan to use a siphon too?