I have a quicksilver 380 with a 25 HP 2 Stroke Merc. This may have been said earlier as it sounds like you have been convinced: Get a 2 Stroke. The gas savings are not an issue versus a 4 stroke. On an average 4 hr day with the kids boating, playing on the beach, towing a tube and generally scooting about we burn about 12 liters or so. That is a really cheap day! Does it really matter if a 4 stroke burns 8 liters? Not much difference to your wallet.
With one person in the boat, it flies. Planes instantly and really goes. With 2 adults and 2 kids it takes a few seconds to plane and is a little slower. Just today with 1 adult and one kid on a large tow tube, one adult and one kid in the boat, it still planed quite quickly. Top speed is considerably less towing water toys so for my needs anything smaller than the 25 HP would not be acceptable. We have a lot of fun on the water with our 2 boys. I plan to use my 380 with an electric motor this fall for fishing here on the lakes around Kamloops. I have a 24lb thrust motor. Should work well I'm sure for trolling. And deadly quiet! I can share more about that once I have tired it.