Use 8125. Each strand can handle 12.2# of draw weight so a 4strand could handle 48.8# of draw weight. That would work very well for a 42# bow. 8125 doesn't creep like D-97 and TS+. D-97 would work too but TS+ creeps and stretches too much. 8125 will stretch for the first couple shots and then settle. 8125 is a very quiet material even more so at 4strands. The bow will be slightly quieter with this material but not a lot until you retune because of the extra power the bow has available. The extra power messes up your spine weight, brace height, etc but when you retune the bow it will be several times quieter. Then just add the silencers of your choice.
The reason a lot of people think bows are louder with fastflight than b-50 is because they tune their bows to b-50 and when they shoot fastflight the tuning is messed up. The messed up tuning makes the bow louder. The same would happen if you tune your bow to fastflight and switch to b-50. So if you change to a 4strand 8125 or other fastflight make sure to retune the bow before you decide if the bow is too loud.
If your making your own string and make it 4strands of 8125, pad the loops to 14-16strands and use a long neck taper.