my yorkie's a climber too.

i ended up getting a second gate that's taller and with bars only so he can't climb it. but i had to double gate it, one in front of the other, for a while 'cause the bars were wide enough for him to slip through at first. sometimes i'd put the ecollar on him so he can't slip between the bars if i'm too lazy to double gate.
i didn't try stacking 2 gates one on top of the other because i think he'll try to climb them anyways. i'm afraid he'll fall back and hurt himself.