Our local "traing ridge" is 1500ft bottom to top. Top at 4300MSL and I've easily reached 3500ft above the ridge 8000MSL and still had a strong climb but had to leave for overhead airspace. I've easily gained more than 3000ft above an 800ft ridge at Jacumba CA from a winch launch.

I've flown in wave off 2500 ft high ridge line (6500MSL) and easily reached 13,500 MSL and had to stop the climb still in 5knt up because of lack of O2 for me and the Pax.
BillT