I have been working on the Hannon Arpeggio on the triads exercises #41 and I am having a bit of a problem with the tuck under of the right hand from G1 up to C2 (it goes C1 E1 G1 C2.. ).In particular my thumb doesn't quite reach the C2 which makes it sound broken up, my #3 finger is long enough (or so it seems) but the tuck under stretch is missing the key.