The vertical diffusive halo size of the Galaxy, \(L\), is a key parameter for dark matter indirect searches. It can be better determined thanks to recent AMS-02 data. We set constraints on \(L\) from Be/B and \(^{10}\)Be/Be data, and we performed a consistency check with positron data. We detail the dependence of Be/B and \(^{10}\)Be/Be on \(L\) and forecast on which energy range better data would be helpful for future \(L\) improvements. We used USINE v3.5 for the propagation of nuclei, and \(e^+\) were calculated with the pinching method of Boudaud et al. (2017). The current AMS-02 Be/B (\(\sim3\%\) precision) and ACE-CRIS \(^{10}\)Be/Be (\(\sim 10\%\) precision) data bring similar and consistent constraints on \(L\). The AMS-02 Be/B data alone constrain \(L=5^{+3}_{-2}\)~kpc at a 68\% confidence level (spanning different benchmark transport configurations), a range for which most models do not overproduce positrons. Future experiments need to deliver percent-level accuracy on \(^{10}\)Be/\(^9\)Be anywhere below 10 GV to further constrain \(L\). Forthcoming AMS-02, HELIX, and PAMELA \(^{10}\)Be/\(^9\)Be results will further test and possibly tighten the limits derived here. Elemental ratios involving radioactive species with different lifetimes (e.g. Al/Mg and Cl/Ar) are also awaited to provide complementary and robuster constraints.