Looks ok. However, my concern lies in why you want high-gravity, high-alcohol in the summer. Summer beers are normally brewed to be light, refreshing, and have the ability to be consumed in quantity. Or am I mistaken?
As far as the hops... It kinda depends on the volume and gravity of your boil. If you boil with 2 gallons and top off with water to make the full 5 gallons, your IBU will be lower than if you brewed with the full 5 gallons.
The 1oz Saaz at 5 mins may only give you 2 IBU. If that. So, if you figure you boil 2.5 gallons (target OG around 1.080) with 1oz Saaz for an hour, you will have approximately 7 IBU. lol. You'll definitely want to go a bit higher than that. Now if you boil all 5 gallons, your IBU will jump to about 14IBU.
Remember, the higher the gravity, the lower the IBU. So if your TG is higher than 1.080 then you will need more hops yet.
BJCP Guidelines for witbier (basically what you're making) call for 10-20 IBU. Depending on how sweet you want this brew, you can choose where you want the IBU to sit.
Personally, I would either up the Saaz at 60 minutes, or choose a slightly higher AA hop. Just my $.02