Jester's showing some frustration and I understand the reason for it. As many, me included, have said, you don't have any low wing experience and, even with an instructor, it's going to come back and bite you as well as damage/destroy your plane. If you look at how a person progresses thought the requirements of getting a license to fly a full sized plane, they don't go from a Cessna 150 or 172 to a Learjet or Dreamliner. They have to go through the steps:
1) simple plane( i.e Cessna 150 or 172 are most common) under visual flight rules
2) simple plane with retracts or low wing with fixed gear under visual flight rules
3) low wing with retracts under visual flight rules
4) the above under instrument flight rules
5) multi-engine under VFR
6) multi-engine under IFR
7) Commercial
This is done so that the pilot can get experience with the various systems without getting them all thrown at him at once. The same goes for R/C models. As size, speed, weight and complexity increase, so do the chances of a mechanical or electrical problem that the pilot must be able to deal with. Without a solid base of knowledge and practice to fall back on, even a slight problem will be unrecoverable. Remember the plane that ditched in the Hudson River? Would someone without all of the training and experience IN THAT AIRCRAFT TYPE have been able to save all the passengers? Probably not when you consider that all it would have taken is one wingtip or engine hitting the water and the plane would have cartwheeled. The pilot was branded a hero since everyone got off the plane without injury. Another example would be an F-14 pilot from Fighter Squadron 1. He had to land his plane on one main and the nose gear due to the other main failing to properly lock down. He not only landed it on the moving flight deck of the USS Kitty Hawk, he did so without causing further damage to the plane. The faulty main gear was replaced and the plane was flying again two days later. So, the question is how does all of that relate to you and the Spitfire? Very simply, you are looking at an aircraft with low stability compared to the trainer you're used to that is much heavier, faster and more complex. One mistake by you, reacting to the plane like you did your trainer, or an engine or radio component failing could put your plane into the ground. Take the time, spend the cash and get some experience with a low wing sport plane before you think about putting that Spitfire together. It will still be there in a year or two but, if you rush things, the odds are it will be in a garbage bag long before then