@acatgirl welcome to the Wen forum and the wenderful world of Wen!!! 
The Tea Tree (TT) TSV kit is a great place to start using Wen. Most of the QVC hosts and Wen models incorporate TT into their hair care regimen. And a lot of the Wenners on in the Wen forum have TT in their hair care routine. -- TT CC is one of the Universal CCs, which means that it works well for most people.
Most people aren't really fond of the TT scent, but most of us get used to it really quickly. And the great hair results tend to overcome any objections to the TT scent.
That said, a few days ago on periscope, Chaz mentioned that while the Tea Tree/Eucalyptus Oil was great for hair growth, that the Pomegranate/Rosemary Oil was the best to promote hair growth. -- Evidently, rosemary essential oil really promotes hair growth.
So, you might want to consider the POM TSV. -- Again, the POM scent is polarizing: Wenners either really like it, or really dislike it. I don't like the POM scent but it works well for my hair, so I'll use it if I have some on hand. -- POM CC is another one of the Universal CCs in that it works well for most people.
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I've never used the Wen oils as a scalp treatment, because I've been making my own 95% jojoba oil / 5% tea tree oil blend (never use more than 5% total essential oils). I'm looking forward to trying the Wen Oils in the TSV for the first time.
When I'm being good, I do one to two overnight oil scalp treatments each week. -- The oil treatments help to gently loosen any excess dried sebum (your skin's oil) off of our scalp. When you cleanse your hair the next morning, that excess sebum gets washed away.
The overnight oil treatments also helped to normalize my pre-Wen very oily scalp. Before Wen, my hair became a greasy oil slick inside of 18 hours. These days, I can go 2-4 days between cleanses.
-- bebe 