I like Sole Paint and Field Paste for treating thrush. The sole cleans can be used as ongoing maintenance but I dont find it so effective at treating thrush. I used Strong Horn over winter to help with soft hooves.
It might be worth checking out Horse Leads as well as Red Horse, as they do bigger pots of their own version of hoof clay and sole cleans for less than Red Horse.
I'd look at his diet too if having long term issues like thrush and poor hoof health, as you'd be amazed the difference diet can make!