Usual practice is to use test flanges/plugs that have O-ring grooves. The O-ring seats on the raised face of the valve flange inside of the RTJ groove. The O-rings of course need much less sealing force.
Testing in a clamp is frowned upon for valves with split bolted bodies (end entry ball...
A wise old piping owl once explained to me that the reason for the selection of 300# (minimum)rated flanges at smaller sizes on control valves (and PSV's) was that almost invariably the piping reduces down a size or two at such valves. The combination of large bore (stiff) piping and small low...
