I have found that there are several basenji body types that are common…
short and stocky, long and lanky, and the slender sleek basenjis with the almost greyhound look about them with gigantic ears. I am sure they are all variations within the breed standard, maybe some have more african blood than others.
Beta, my girl was alwasy 19lbs from 1-1/2 years through adulthood. She was a small basenji compared to the other girls she played with.
I believe boys should not weigh more than 25lbs for the breed standard. Caesar is 24lbs. and has been that weight all of his adult life.
If I remember correctly, after they are 7months or fixed they tend to look like string beans for a while or gangly teenagers. Then they start filling in or building muscle.
Cairo weighed 15.9lbs at his neuter date (almost 6months). He is still smaller than Caesar but proportioned like a mini b. All of his teeth are finally in. I have noticed that his head has gotten larger, but his chest is still small. I have also noticed that now he will eat more food than before so I expect another growth spurt is coming.