Stephen, despite the back that the aforementioned backback sprayer carries smaller volumes than a large tank sprayer, it doesn’t impact the concentration of the solution one is applying so I don’t believe ‘burn’ would ever be an issue. What it does impact, however, is the total volume of material that you can spray before having to reload your tank. I mix in a 55 gal drum with a manual pump and the refilling process goes very quickly. I prefer that annoyance over the annoyance of the weight of the regular sized Stihl backpack sprayer. The tank volumes of the two sprayers are available on the Stihl website and thus the weights for each of the fully loaded backpack tanks can be easily calculated. As I see it, tank volume (but not concentration) is the only limiting factor.