The Puddle is designed for elevator and rudder only and it works great in any of the sizes
My Monster only has E/R/T too.
I made a Small Puddle with ailrons and it works perfectly
very aerobatic! I did however make the wing with no dihedral at all..
So really depends on what you want, if you want it easy like a trainer build it with no ailerons, if you want it a bit more complex build it with ailerons.
The wing is VERY VERY easy to build, so you could make one without for your first try and if yu feel the need for ailerons just make another one... i need about 30 minutes to build a Wing with the Puddle Twin design...