Probably not enough. Bear in mind that ever since ULSD replaced LSD, many people use lubricity additives to make up for the loss. Not that it is entirely necessary, in my opinion. Supposedly sufficient lubricity additives are added to ULSD to compensate for the reduced sulphur.

So if you blend with JP8, you're reducing lubricity in the ULSD which is already at minimum levels for the 7.3.

By adding just 2.5% biodiesel to ULSD, the increase in lubricity far exceeds any additive you can buy.