Stitching theta v

Hi all, I am having a nightmare trying to stitch HDR images generated with photoshop and the dual fisheye plugin. I am extremely reluctant to spend over 150 quid on an app just to stitch images. Can anyone suggest other ways of stitching Theta V images, I have tried Hugin and almost got it spot on but have one issue where the stitch is bad and have not been able to sort. Really hoping for straight to the point solutions as have been going around in circles for three days. Kind regards.