Just want to jump in here. I am testing out the hashtag strategy as well. My acc only has 6k followers. So what I have been doing is:
I take a high competition hashtag which I would have used in the past
Go to Websta.me, type in that hashtag and it will give you all the lower competition hashtags (I only choose hashtags between 1K - 14K)
I then use these
I did decide to go with very low competition hashtags (mostly 1K - 14K), But I dont use all low competition hashtags. I think when I do this I will get even better results.
Using this method I found that my posts are getting into the feature section.
At the moment I am doing a massive unfollowing (so I am only getting 400 likes per image on average), but usually with this method I get 500+ likes per image and good engagement.