Trac Tack Mint = Build Bite (needs time to cure)
BTrack Tac Black Sand
Kryptonite on the inside to build bite and will drop duro a little
Grape if you need to soften.
At the track use 1/2 acrysol 1/2 black sand as a prw
Depending on the abrasiveness of the track (Salem Speedway in Oregon for example) is VERY abrasive despite being VERY lowbite, you want to be careful not to drop the duro too much, focus on heavy conditioning.
Cold and wet
2 - 3 oz internally with a mild prep (hot lap 2, venom juice original, track tac tire tuff and sst 50/50)
Outside I would scuff the tire first before wiping anything. Tires will drop on durometer from inside prep. Then wipe a wet track style prep (venom soak and blue 50/50, track tac grape and topaz 50/50, krugs mixed down with hotlap or acrysol may even work) watch the durometer Vegas will soften very fast in very few coats. Basically just wipe to duro or amount of grip you need.
Cold and dry
1-2 oz internally same inside as wet
Outside scuff the tire same as wet. Prep choice is different here (venom bite black 5, track tac black sand/grape 50/50, venom bite blue or track tac blue) hot lap 2 may even work wiped uncut. Really depends on track conditions, moisture, and night or daytime. Blue will be more geared towards a light moisture, blacks will be more for a dryslick/dusty, hot lap 2 would be a standard not so aggressive prep that will give mild bite and soften the least.
These are options you have. Depending on what prep line you choose stick with it. They should have something for about every condition on a Vega. Vegas are a simple tire to use. Just have to be light on the prep. Vegas have a lot of natural bite. And once they soften most of mine havent come back more than 5-8 points. So dont get carried away wiping right out of the box. Wipe 2 times and see what they've got on track. Gauge from there.