Regarding Scientific kits, the wings and tail surfaces almost always match the plans. Your Super Stuntmaster (and the standard Stuntmaster) both have low aspect ratio stab/el assemblies, with a somewhat elliptical tip shape. I don't know what your tailfeathers actually look like so cannot comment. But please make them as per the plans.
For Scientific Hollow Log fuselages, the situation is a bit more murky. For example, on the popular Little Mercury, both the box art and plans show a canopy (and pilot "hole") position in a rather aft position. However, many of the (later?) kits simply supply a Stuntmaster fuselage, which, although similar to the Little Mercury fuselage, has the canopy much further forward. But, usually, everything matches between plans and the wood you get.
Scientific makes cute little mistakes. In the F-100 kit, they have a little artwork picture of an F-86. And they played with span changes a lot (the Little Bipe has no less than 4 different advertised spans per the print ads; whether this actually happened, I can't say. Walt M. didn't think so). The original Thunderbird bipe ad says 18", but every one I have seen has 15", per the later ad.
By the way, your Super Stuntmaster, with the 20" built up wing, should fly well. My standard all wood 18" Stuntmaster flies OK, and yours should do better. Use a double ported Black Widow Cox if you like, but a standard one lunger Babe Bee is just fine. For the Musciano Meet, you must use a single ported cylinder. Please don't use Dacron lines, either.
No less than five Scientific Stuntmasters (Baby, with solid wing but built up fuse, Giant for .35s, and the 1948 ignition version) altogether! So little time...