Will an octane tester be able to show the final octane once I have blended BOOSTane?

Unfortunately, no.  The reason is based on how these devices determine the octane of pump gas in the first place.  The way a handheld octane calculator works is by measuring light, refraction through the fluid.  Because octane in pump fuel is increased with typically the same chemicals, just different concentrations, these devices are calibrated to measure those concentrations with light refraction caused by these chemicals. However, with BOOSTane, since our active ingredients cause different reactions with light, the resulting octane may be extremely high or not react at all.  A drop of food coloring may cause a higher octane on the device, but we all know, it won’t cause higher performance in the fuel.