OK,
I use thighs for the basal... (I'm ready for bed any ways.) it's also goes back to the days of glass syringes & the training so I'm comfortable with the rotation in that area... I also use that site for bolus if on holiday in shorts. (Lol, the only time I wear shorts.)
I always "pinch up" on every injection.. I still use the stomach for the bolus but work it round to the sides, just below the ribs..
I'm a skinny guy but still find the 4mm needles disappointingly painless since starting MDI a good 28 (calculating it now.) years ago.... That's all I can say.. I believe I do have a high threshold to pain any how.