When I'm about to stand up to climb, from my lowest gear of 30f/27r, even at that lower level of mechanical advantage, I'll click off at least two or three gears before getting out of the saddle. More torque, less cadence is typically what you do better when standing. For the 26 chainring combo above, you should plan on sitting, I can't picture really standing and grinding out that kind of gearing, though YMMV.