Crazy Nick....you have a good question there. Moving the engine forward and/or lightning the tail of your Sig will get you balanced without adding weight. No question, you can force a square peg through a round hole is you apply enough force....I don't recommend that method of building. I have seen way too many models where someone was too lazy to do the job right and took the easy way out, and just bolted on some weight instead of planning the distribution of weight from the start of the build. Result: Over time that added weight destroys the airframe with each landing and each G force applied, resulting in a shorter life of the airframe and in some rare cases airframe failure. With just a little planning you can dramatically limit or eliminate added nose weight in almost all models...with the exception of the really short coupled ones. Congratulations on building a light model without sacrificing the structural integrity of it...not always an easy balancing act to pull off.