If you can’t swap out the shafts then there could be a way to use them. If you’re using a non-fast flight string, and you can build out the strike plate a little to say 1/8" out from center, if the bow is not already there, you just might get those to shoot for you. Building out the strike plate can go a long way to get that shaft shooting. If you stay with the standard insert, draw 29", and cut shafts to 30" to start you might get it to tune with 125 or 145 heads someplace between 30 and 29.5”. Put in some weight tubes or something in the shaft to get the weight up. Also I think you could foot the shaft and stiffen them up that way while also adding some weight, but I am not sure on that and don’t have a lot of experience. You can put in knock end weights; that will give you weight and stiffen the shafts. I think 4-fletch and also wraps will stiffen the shaft. There are a lot of options.