Between 15 and 17 weeks please? Roughly. He's a tibetan terrier. We are obviously weighing fairly crudely - bathroom scales, one of us holding the puppy, but according to our records he's put ion 1 kilo in 2 weeks. Does that sound about right?
I tried it for my crossbreed - staffy/JRT and it gave me the same adult weight for either (essentially, JRT size). At 5 months it does look like she will be essentially a staffy-shaped JRT or should I say, a mini staff!
I think rather than trying to weigh (which doesn't allow for the individual breeding of your dog), you should do it by feel, put you hands on the side of your puppy, on ribcage - you should be able to feel his ribs with gentle pressure of your hands (also moving slightly backwards and forwards) - they shouldn't be immediately obvious to the touch, but you also shouldn't have to press too hard. I would talk about seeing a nice tuck in, but with all the hair a TT has - that won't be possible.