Hi guys

i need a hand with gearing my new xray i just cant seem to get my head around it

i got 2 motor's i run a 27t quad demon and a 15t team orion

what gearing should i be using for these motor's in my xray im using 0.48 pitch

the spur size's i have are
84t
78t
93t

and my pinion size's are

21t
28t
33t
34t
35t

and what gear ratio am i looking to be getting from it which is better a high ration or a lower ration and how will i know when i have the right gearing

i want an pretty high take off speed, as i usualy race on small track's but i like a good bit of top speed to