[9cao]

If you measure variance in terms of BB's per 100 hands then increasing X only reduces the variance of your variance and not the actualy value after 100 hands.

Variance will always be higher in the typical low-limit verus typical higher-limit. Bad play doesn't reduce variance, it simply increases your win-rate. If I played a slightly +EV lottery with you where you had a 1 in a million chance of winning or if I played a zero EV coin flip game with you where you had a 50% chance of winning the variance is obviously higher for the lottery.

If you use a different measure for variance the answer to your questions is much different.