Driver with good off axis response will normally have bigger sweet spot. If you don't normally listen to music on one spot, good off axis will be something you looking for. However, top quality driver from Seas and SS don't have good off axis response. As always, there trade off.
Good 60D off axis with flat response driver is hard to find so far I only found these.
For midrange Seas 4in MCA11FC, if you can find it. For midbass, Peerless 4in 830854, 830870.
For tweeter, have a look at OWI and OWIV.
The best is download the catalog for each manufacturer from Madisound. If is easier to find what you looking for.
Have fun
