Scissor lift advice

This is more of a quick question about designing a scissor lift. I was wondering if my team should go with a 25 hole length C-channel or a 35 hole C-channel. I know that longer bars can bend easier, but have any of you had any issues with the longer length bars bending under force? Also on our current design we have gears inside of the lift to lift the mechanism. In other teams experiences, is having the gears inside of the jack more effective than driving the jack at the base?

You might have a look at the conversation taking place at this on-going thread, especially starting with post #8: