The Nordic Weightlifting Federation uses Q-points to determine the Best Lifters at Nordic Championships, both for Seniors and Juniors (U20), with slight restrictions to the lowest bodyweight categories (see text below).
Direct link to calculator: <h4>Weightlfiting performances <br/> Bodyweight adjustment</h4> (shinyapps.io)
Link to site with explanations and Excel formula: https://osf.io/8x3nb/
A group consisting of Marianne Huebner, David Meltzer, Asgeir Bjarnason, and Aris Perperoglou have published a paper on their work which explains the method and compares the Q-points with Sinclair points and discusses short comings of Robi points.
According to the authors the Q point formula works for youth with some restrictions. For males the original unfiltered dataset has over 15 000 results of which only a handful were for bodyweights under 48 kg. Thus the formula cannot be used for bodyweights below 48kg for youth males. For youth females the limit is at 43 kg.
The challenge with youth lifters is in the comparison of pre-teen athletes to athletes who have gone through puberty. If one holds a youth competition and wants to determine the best lifter, one can compare the same aged lifters to each other: the best 12-13-year-old lifter; the best 14-15-year-old lifter; and lastly the best 16-17-year lifter. Yet the lowest bodyweight to consider is 48 kg for boys and 43 kg for girls until the study can be completed with a sufficient database of results for lifters under those weights.