I would soft mount the 115.
I just installed mine in a new stiletto. When I grabbed the needle to start the breaking in, I couldnt believe the shaking. I could hardly hold onto the needle wire extension. In fact it ended up cutting my finger. Soft mount is a must for longevity- period.
I saw one of these hawkers fly at Speedworld with a YS140 and it was Gold Fast.
Should be a good set up for Silver with that 115.