Using Motul v300 10w40 fully synth in my GTV and have recently Millers Competition 5w40 fully synth on the 147.
I've swapped between various grades (10w40 fully synth, 10w40 semi, 10w60 fully synth and 5w40 full synth) and makes (Selenia, Castrol, Agip, Mobil, Valvoline, Motul, Fuchs and Millers) over the years. So far, i've never noticed a difference in oil consumption - the GTV uses hardly anything after 80k miles and the 147 uses an incredibly ridiculous amount. But I did notice the Selenia and Mobil got very black very quickly so moved away from those makes. All the others listed I like and will try the very expensive Millers Nano Tech on the next change .