He sounds like he's about the same size as my girls. One is about 80g at 16.5in the other is 100g at 18in. If your boys is almost 2ft long, he's probably 100-150g. I would be feeding him a rat that's about 10-15g (usually a rat fuzzy). If you can get a scale and weight him, try to feed him about 10%-15% of his body weight every 4-5 days. My 100g girl gets a rat fuzzy every 4 days and my 80g girl gets a couple of rat pinkies or a very small rat fuzzy.
I'll get a scale before I try to feed him again. Thanks