Hi Tom,
I pretty well much agree with all Steve has said. You should glue on the nosecone, if it moves around it's curtains.
The spit is a nightmare to trim, the wing shape is not ideal for the low speeds and stability. At the end of the day the real thing had a huge lump of metal at the front in the from of the mighty Merlin, and was also designed to fly fast, unlike our little models.
A major problem with the Guillows stuff is the nosecone, there is no provision for the thrust adjustments that you need to do. On the cessna build I've managed to come up with something that might do, but it's still not ideal.
Go with that scrach build, the FROG designs are nice but again there was never any provision for a noseplug, and most have sheet tail feathers (therefore Making them tail heavy from the outset), and the construction is what you could politely call "robust" I do like them though and they do fly, so there could be worse choices.
http://youtu.be/0A1q1wv9ZiMIf you PM me your e-mail address I'll send you the plans for a couple of keil Kraft designs that are high wingers, have a proper noseblock and if built straight WILL fly.....They were designed by the legend who was Albert Hatful.
Andrew