DCC conversion for Thomas engines?

[Greatgoat]

Wondering if anyone has tried to convert any of the Thomas series to DCC.  I'm trying to convert the engines to DCC so my son can run them at our club layout.  Any help or input would be great.   I need some idea how to wire and maybe which scale decoders might fit into the engines.  Might possibly want to put sound if there is enough room.  I currently have Thomas and Gordon engines. 
Thank You,

[pdlethbridge]

this site has a lot of installs including Gordon, Thomas, Percy, Toby and James
http://www.tcsdcc.com/Installation_list_by_Manufacter.htm