I agree with Ash, be very careful of engineering firms who undertake rebores on Jap bikes. I had an engine rebored and advised the engineer of the Honda specification for the piston to bore clearance. The engineer rebored the barrel oversize. When I asked why he told me the piston would sieze if he bored the barrel to the Honda spec! Result: the engine used so much oil so quickly it siezed! I had to find another barrel, a new piston, rebuild the crank, new con-rod and regrind of the cam as a result. I went to another company to get the rebore the second time! A very expensive lesson.
I have never personally used Trigger but I would have no hesitation to do so in the future, he knows these engines better than anyone else.
Good luck with your quest to buy a sohc, you won't be disappointed 👍.