Oops, forgot to ask. If you use only D-12 motors in a stock configuration, do you still have to add any one weight to prevent lawn darts? Or is that only for high power motors?
I've only used D12 motors in mine and I would say that any weight would make lawn darts more likely, not less. (The commonly-referenced lawn dart problem is apparently typically caused by the nose-cone shoulder allowing the ejection charge to vent without deploying the parachute, nothing to do with power or weight.) Mine was stock and I've had some deployments very close to the ground. Add weight and it won't go as high, making that problem worse.