leaves have been burnt, topping help? pics

Okay so i'm growing indoors under four 75watt cfl's and my plant has grown into the light, i've raised the light now but its burnt pretty badly on one leaf particularly.

they are not very bushy plants, and i was thinking of topping them so they grow bushy, and the top burnt leaf will be cut off. im not too familiar with this so could someone tell me where to top it at?
in the first pic is the burnt leaf at the top of the plant. in the next ones is where i plan on cutting the stem off. ( circled the area) also do i cut below or above the circled stem??

thanks!
blaaze

oops forgot to post pics here they are

.................

thanks that helps alot! is it too late to top if they are almost 2 months old?