Some people though it felt quite heavy while some thought it was light and fast on the string. Personally, the 7075 version is a beast. A definite change that needs to be made is the rims though as it can draw blood. However, I am designing this with my brother in mind and his style tends to lean towards the "Iori Yamaki" style so I am considering shaving off a few grams and readjusting the weight distribution.
Fast and stable then? sounds like fun.
Post more pictures, and maybe a video of your brother.