Use bud candy it makes just about any strain alot more dense.
just remember every foot your losing 100 watts, so if it's 4 feet away your losing 400 watts, on average, it just depends how hot it runs, I used a raptor hood and I was able to have the plants touching the glass because I was cooling it so there was no heat issue.
Mainly buds don't get dense because they didn't receive enough light, always ensure they got enough so you don't get airy ones.