Looking for best selling T-shirt Design research

I am looking for best freelancer who will research best selling T-shirt designs from different niches. Freelancer must have good experince of Teespring and finding best selling & winning designs. After finding best selling or winning designs, freelancer must do tweaking or modifications in best selling or winning designs to make it better or attractive. I will offer the said price for 30 such designs.

Please note that if I will be able to generate good revenue on Teespring from your designs then I will provide you great bonuses and I will work with you for long term.