15" hinged is the most common. You can use smaller but the 15" hinged is really the best option. I suggest a level 1 stand for the MLT and and a level 3 for the boil kettle, add a handle for easy in and out. With the level/stands you will want to choose "reversed" hinges, but don't worry if you forget that part we will see it and take care of it.
Cheers
Jay
How much loss in their usually with the 15" version?