The current generation of "2 metre" f3a models snap better than earlier ones, and they have smaller wings
than your Atlantis.
Have a look at the designs for Oxalys, Beryl, Integral(New Stephane Carrier model @ Zn Line), Genesis---They'll all have wing spans near 74 inches (1.88 metres) and wing area about 950 square inches(sorry, don't know metric for that!)

But---have you tried different control settings just for snaps? My Abbra (Made in the Czech Republic!) is OK for single snaps on my normal flight settings, but needs much more aileron. a little more elevator, and less rudder for anything more than one.