controlling bending and distorting isocurves in the u and v direction

hi all

im quite new to grasshopper and i have ran into a problem regarding isocurves on an untrimmed surface.

basically im trying to bend/distort and control curves on a complex surface, like ive shown in the sketch below.

ive started a definition which basically divides the surface and extracts the iso curves and then listing those. im stuck on how i pick between u and v isocurves and how i would control certain one's....and also how i would bend and distort these curves along the surface. i hope my description is ok!

any help would be greatly appreciated.