The 5 wraps 28g didn't sound too promising TBH, though I'm glad someone did build it and try it out. It's a potentially (in reality longer of course) a 1.6mm long coil, whereas 10 wraps 26g is 4mm. Surface area, which is a balance between length and diameter (which obviously relates directly to circumference), is an important factor in achieving ideal flavour. Diameter also allowing more wick for increased juice consumption especially important at lower ohms. Of course ramp up time dependant on gauge of wire, wicking material, and juice viscosity, are factors as well.