Seat tube length: I would like an option to choose a certain top tube slope instead of seat tube length. This would be useful for example if you want a horisontal top tube.
Front end height: I suggest adding other options than stack for controlling the height of the front end. I would sometimes like to enter the headtube length in mm instead of stack. This is useful when you already have a headtube cut to a certain length. Among the choices could also be handlebar drop in relation to the saddle and/or other dimensions locking the handlebar height.
Thanks for an amazing software!