I have a Logitech G600. The side button placement isn't quite right for my relatively large hands so I can effectively only use the front two side button columns with my thumb tip and the rear three...
odd your hands seem too big.
i'm 6'2" with a 13 1/2 shoe so also have relatively large hands.
have never really seemed to have problems reaching the side buttons.
though i do mainly also only use the first 2 rows in games.
set as Home, End, Numpad +, Numpad -, PgUp, PgDown.
I only wish there was a way for WoW to directly process mouse buttons instead of having to go through keymaps that may interfere with each other.
i keep G15 as Enter, G17 as Backspace, and the other 4 from the last 2 rows as the arrow keys.
with ring finger button as Right Ctrl, scroll wheel click as Delete, and G7 as the actual middle mouse button.
really makes browsing and editing text super easy.
also gives me plenty of extra buttons, as keys that i would never actually assign in-game, in all of the games that i play.