Deciding on Aluminum Pontoons for a Shanty Boat

I am deciding on aluminum pontoons to make a 25ft shanty boat to float around in the summer here in Berlin. It would live in the water and go very slowly so it's not in any danger of bashing into anything at high speeds.

I am going to buy 2 already-made aluminum pontoons and my questions are,

How thick?

Which Aluminum?

The two options I have seen are 5052 at .090 and 5083 at .125. Buying from China or Poland. 5083 is unfortunately twice the price of 5052.

I know that 5083 is stronger but is stronger necessary if this boat is going to have such a slow and easy life? I would love to get the 5052 now rather than having to save up to get the 5083, but in the end I want to get the right thing.

 

Yes!