i use on my staffs that i sell... 50cm of 4 inch wick on easch end as a base
this gives a really good visual burn time, as as the tick is wrapped tightly the fule can not escape as eaily as with a lose wick, meaning teh fire draws it out better and thus a better burn
if you wish to extend you wicks then butt up next to it the desired length
i would start with adding maybe about 2inches to your 4, or if you wish add 4 to four right up next to it
this will give you a differnet style flame size, and a larger flame at burn off, but more wick means more fire, so be carefull, you dont wnat to have so much wick the staff is unusable due to teh lames lick up the staff and burn your hands, and also yuo dont wnat it to produce so many fumes that it makes you ill
the most i have had on a staff os 16 inches, and taht hurt!
the flames rose up teh staff and burn my hands so that they tingled it was not very nice, shorty afater the staff was killed and teh wick used on different toys!
if you can have a look at other peoples stcisk around you at your next meet, you might find a 6inch flame is teh right way to go for you
strugz has a 6inch wick after he saw mine a while back, and taht what i like, although at the mo im using 4 inch wicks ill be going back to 6 when i make my new toys

enjoy