ok. Thanks.
I will say at 18 years old, IMO your too young for steroids. and, at 5 ft 11, 190 lbs, your light as well. Your natural test level will never be higher than it is now, and you should take advantge of that and grow naturally over then next few years, and then do steroids if you choose.
If your going to do them anyway, look around and see why test should be the base for any cycle. A var only cycle may give you some gains, and your 6 lb goal could be reached with proper diet/rest. 50 mg for 8 weeks is what I would run, as var takes a bit to get going. You will need a PCT with the var cycle, look into a light clomid/nolva combo. PCT will jump start your natural test production, and even with var only you will be shut down.
In closing, I do hope you decide that running steroids is a bad idea. With so much more natural potential left you are really short changing yourself by using them now. Plus, when you come off cycle, there is alot of emotions and things that come up as your natural test balance is all fucked up. As an adult it was tough for me, and you really need to be mature to handle it. IMO not many 18 year olds are mature enough, please keep that in mind.
One more thing: once you cross the bridge there is no going back, and at 18 years old I dont think you fully understand what that means.
hope this helped.