I'm not an expert in any way, but I did make 25 gallons of Sangiovese in 2020 the night after I stayed in a Holiday Inn!
Sangiovese is a fairly light bodied and light tannin, moderate+ acid wine. With that in mind, I'd go at the very low end of the oak recommendations and probably avoid M+ as too smokey.
If you are thinking cubes, use the dose calculator published by StaVin
here. I think in Italy, Sangiovese is typically aged in neutral oak, so keep that in mind too. For mine, I dosed at 20% of "new" levels, used Medium toast and I'll check monthly aiming to have it off the oak before you can even identify the oak flavor. So I'm aiming for a hint of oak rather than a blast of oak.
It has seemed to me that if your wine has more tannin, that will balance well with more oak. Since Sangiovese is low in that regard, I'd aim low on the oak addition. You can always add more later, but you can't take it out. I learned this lesson painfully in 2018 and it is still haunting me.
Good luck, I'm still learning too, and just sharing a bad experience to make a point.