There is no load on the upper wire fitting during flight unless you subject it to a negatve G force the only time these wires are loaded is when the plane is on the ground and mabey possible during a very hard landing as for modifying your fly-baby bi plane I would recomend that you stick with the plans as these are proven when you make major changes you then have a unproven product and you become a real test pilot as for changing the gear I recomend staying with the stiff gear with the 8:00 x 4's if you go to a suppesion type gear then you will need to reinforce the attach points and the bulkheads (the proper way would be to install a cantelever center section to support this new type gear) which would absorb the new loads imposed on the attach points. These are just thoughts I think you should consider as I changed the gear on my Fly-Baby Biplane and this is the route I had to end up taking as the flexing of the suppension type gear elongated the attach points in the bulkheads where the gear attaches so I built a tube steel center section to support the gear now the problen is solved (add about 150 hours to build time to manfacture a steel center section to a uncompleted airframe and about 200 hours to a completed airframe. Truthfully if I had it to do over again I would stick with eather the original stiff wooden gear legs or the modified tube legs that Pete shows in his plans Goodluck joey