I'd agree with Andy and BTerry however, as far as point 3 is concerned, I would aim for scales that produce an average AUW and wing loading. If the power plants are to be standardized (whether electric or glow at say 250W ~= 0.33hp) then ideally the wing loading of the models would be kept appropriate for such plants. Since the planform changes from one design to another, then the wing span can be scaled to result in a MAC that produces something on the order of 200 squares (~1.38 sq ft).

In other words, I'd reverse engineer it as they say. Figure out what wing loading you want for the models, obtain the number of squares required for the AUW you're aiming for (I'd think something on the order of 25-30 oz) and then see what scaling results in order to produce a wing of that many squares. In all likelihood you'll see the spans ranging from 38" to as mcuh as 45" I'd Imagine but that's cool. As long as they all end up weighing the same, have the same area and same plants, then the rest just adjusts.

One good example of this sort of design approach was Fred Reese's 1/2A HOB stand-off scale series. They all weighed around 22-25 oz and had 36" spans. In fact, the wings for all 5-6 models are essentially the same with subtle differences to the planform to make them more scale like. In this case, I like Andy's concept of keeping them as exact fractional scale models and just have the size fall where it may.

Regarding foam/built-up, I think that's entirely up to you Don. I think (pattern) builders are accustomed to both but your average new builder might be more at ease with a built-up if their experience is with ARF's (or none at all). Personally, I like the end result of foam core wings and they can be built to be light (My Pico's at a fully sheeted finished weight of 7 oz weighed perhaps an ounce more than Raindave's built up UFO wing at similar scales/loadings) and truer. However, it's possible that on models this size, built-up might go a tad faster and might be lighter if ribs are appropriately re-selected.

Stabs, again up to you. I'd say go with whatever is easiest from a kitting stand point. I think the weight of finished foam core surfaces is likely to be more constant assuming you select the sheeting. With built up, the weight may vary a tad more depending on how much care is put into the wood selection - something which is time consuming when kitting.

All said and done, I really like the look of authentic reduced scale pattern bullets - mini versions of their big siblings with all the details that are practical and sensible to include (i.e., retracts, anhedral stabs, airfoiled empennage, etc.)

I look forward to the continuation of the Eyelash!

David.