I'll try it straight in first and then see how it feels and go from there.
On a side note, I have MMT 105 TX in my 4 iron and that works really well, have demoed 105TX in irons too and that felt stable and couldn't tell it was a 113g shaft as it felt head heavy.
Tried MMT125 stiff and that felt like it had more movement than the 105TX (still stable) but I didn't mind that at all as the heavier and slightly softer shafts does help with smoothing out my tempo.
Previously coming from PX6.5 1x SS.
Thanks everyone for their response though.