Thanks for your interest and questions, Dr. Barkan. BR powder is certainly a convenient option. Though, without knowing the nitrate content it is difficult to make a recommendation. Moreover, as I'm residing in Germany, my sources may be different from yours (in Australia?) But I'd like to point you to a study that investigated the different supplement options available to athletes (https://journals.humankinetics.com/view/journals/ijsnem/29/4/article-p345.xml).

My personal experience: nitrate content of BR depends quite considerably on cultivar, growing season, and harvest timing. Even if the same cultivar is being used, nitrate content may vary. I have used powder in the past (blending it into my regular breakfast smoothie), but I returned to taking the BR juice (my choice brand available here is Grünfink). There is a possibility to check the salivary nitric oxide levels, which gives you an indication of how one product compares to another. The company Berkeley Test LLC sells NO saliva test strips for that purpose. These strips indicate via color intensity the possible NO yield from your diet or supplement.