Toe overlap is the dimension between the tip of your shoe (with the foot on the pedal at the most forward point) and the front tire's back side. Front center is the distance between the BB center and the front axle center. The two relate to each other. Some riders have more issues if the tip of their feet contact the front tire while turning then others do. Just one of the questions a builder will probe with their customer.


" If you have to replace the seat stays then all tubes attaches to the Bb are free for alignment without effecting other tubes directly." means that if the tubes that are joined to the BB shell are not constrained by their other ends (by not having a closed loop or complete triangle) they will be easier to move about to effect alignment. If the seat stays were left joined to the chain stays and also left joined together (at the bridge or seat cluster) then no independent vertical movement of the chain stays will be possible.


This comes from doing enough repairs and such on frames to know that many are not all that well aligned from the factory. If I do a repair I assume the job of frame alignment being right after, regardless of if the frame was straight before.


Back to the rider's seat height. Can it be accommodated with the seat tube left as is? I still am not sure if this is the case. It would simplify the job a lot if this were the case. Andy.