FLYINROG,

7X6 for speed, or 7X5 APC, 8X4 APC for more vert.
Short plug from your favorite manufacture- Fox? Enya? K&B? or?
On my small (.15 and less- including the Cox engines I've converted) I pop off the head, and check for clearance, just to be safe. The farthest reaching part of the plug should be flush with the inside of the combustion chamber. If it sticks out into the chamber, use an extra copper glow plug gasket. I have never tried a plug with the idle bar, because the "idle" speed is high enough they don't seem to need it, and have never had a problem.
As for the spraybar model, don't know if it's good or bad, but Enya's are all good engines, so I wouldn't worry to much.
Hope this helps, let me know.

Jetts