You mean if he leads into you? That wouldn't be cbetting, but leading or donking. Cbetting means they were the aggressor on the previous street(s).
You shouldn't be stealing a set range, but rather stealing as much as the blinds will let you. It depends on a few factors, mostly how well they fold to steals, but how well they fold to barrels, how much/little they 3bet from the blinds, how much they donk bet, how often they fold their donk bet to a raise, etc are all important.
The big one being fold big blind to steal, I open any two if their combined stats are 140 or so, but may tighten up if they 3bet lots, or don't give up well postflop.
But ya, if they adjust and start fighting back, you have to either tighten up or test their donk bets by raising or floating them.