Welcome in!
the good news is that tobacco keeps. almost indefinitely. The WLT kits make about 15-20 cigars depending on how you roll them, it's a great way to startout before you start trying different blends on your own.
if you want to buy poundage, the WLT site (ad at top of page, sponsor of forum) has a number of variety of fillers, binders and wrapers. it's hard to answer the question of what is the right amount.
seco makes mellow, so if you want a smoother smoke you will use more of this.
viso makes a stronger smoke
ligaro makes the strongest, so if you like dizzy and nauseous...go hard!
there is lots more better information here, just wanted to say there is no perfect blend so you run out of tobaccos all at the same time...but you won't waste any, it will just stay sealed up until the next batch arrives or is grown and then the blending madness sets in again.
i would however suggest a higher pound count on seco. the stonger leaves...what can i say, for me a little goes a long way.
if you are anything like the rest of the guys here, it becomes a collection in no time.