Hi and welcome to the forum!
Just checking through the rides list I think the below list would be best suited (this goes on what I have seen in the past, and myself with a 46" chest)
TH13TEEN (Strong possibility)
The Blade
Nemesis (if you choose the big boy seat)
Oblivion (if you choose the big boy seat)
Enterprise
River Rapids
Hex
Duel
The Flume
Enough there to keep you amused all day

Also! Don't forget there is "test seats" outside some of the coasters you can try before you ride

And, check this
http://forum.towerstimes.co.uk/alton-to ... ns-on-air/ there is some guide lines on the sizes for chests.