From what I understand, the difference between a full size and a smaller size is weight and horsepower needed to move that weight. In otherwords, if you want a full size DH-4 capable of moving as fast as the original, you're gonna need a good size engine in it, putting out horsepower comparable to the 400hp the original Liberty engine did.
With a smaller scale version, it will weigh less, and not need as big an engine, which all adds up to saving money. The thing is, if you have money to burn, I'd go for the full size version. But that's just my opinion. And I don't have the money, or a pilot's license, nor the money to take lessons. Wish I did though.
Hell, who am I kidding, I would rather not be diabetic. oh well.
Later,
Al Lowe 'Honourary Canuck'
'Semi-Official
Billy Bishop Booster'