Will65 Agreed. The most objective way to judge what performs well with the broader SLR audience in general is to look at the top performing videos and the casting for those videos. For the past year, this has meant mostly beautiful young girls who are new to hardcore VR.
Not everybody is into that, and that is ok. Niches should also be catered for, but you should not expect niche videos to be as popular as mainstream porn.
The key here is balance. Continue to mostly cast young, beautiful girls new to the industry as these make the most customers happy. But also have a portion of your videos dedicated towards niches so that those with other tastes also have videos they can enjoy.