Do not know answer, but I tried to find Vietnam seat cover only for a police solo without success. I would even like to find G5 / Convert standard tandem seat cover. It looks like the Vietnamese stock repop 2-up seat covers for the T3 are smaller than Convert. Please correct me if I am in error and they do exist.
Otherwise, it looks like Harpers solo seat, would be most effective solo seat in the long run. I do not think Harpers has a police solo seat, but maybe I am wrong there too.