At 1800g, you could be feeding up to medium rats I believe. I have my 1200+ gram normal girl on smalls. She could probably take bigger, but she's a wuss and is scared of some of the bigger "small" rats.
Kevin Johnson
0.2 Normal BP -- 0.1 Pastel BP -- 0.1 Spider BP -- 0.1 Het Red Axanthic BP -- 0.1 Ghost dinker
2.1 Het Pied BP
1.0 Lesser Bee BP -- 1.0 Pastel Yellowbelly BP -- 1.0 Mojave BP -- 1.0 Black Pastel BP -- 1.0 Cinny (poss het ghost) -- 1.0 Champagne