@mirolab
I just upgraded my Modwright PH9.0 to the XT and I haven't really had the time to do any A/B stuff with and without the SUT.
Being pretty lazy and having a couple of 0.2mv carts, I just kept the SUT in there.
I really should compare. Before the upgrade I did some A/B and didn't notice a drop off so I just kept them in. I do loose some dbs using the just PH9.0.
I do have the switchable build. I mostly use the 1:15. Sometimes I use the 1:30 if the vinyl is really quiet. The gain on the Modwright is already high so sometimes I even use the -6db attenuation. Silent for me.
SUT placement is kinda critical too as it can pick up all kinds of hum.
I went with the 7s cause the gain on the 3s is kinda too much for me.
I don't know what the MC stage in the JC3+ is, whether its a SUT or active. If it's active, I'd give the Hashimotos a try. There's also the HM-X.
At this point I'm liking the sound with the XT upgrade and the SUT so kinda don't want to mess with it!
Hope that helps.