A black hole would radiate mass optimally for interstellar-travel applications in the range between $10^7$ and $10^8$ kilograms. Assuming a light-only radiation emission spectrum, with a parabolic reflector with efficiency $f$, this would create an acceleration
$$ a = \frac{f P}{mc}$$
$$ a = \frac{ f \hbar c^5 }{ 15360 \pi G^2 M^3}$$
$$ a = \frac{ f 10^{24} m \times sec^{-2}}{M^3} $$
The problem is that the schwarzschild radius at this mass is a few attometers, which creates a host of problems:
1) the rate at which it can feed from normal matter is too small compared to the rate BH mass is being radiated
2) any electric charge we throw in the BH will be quickly radiated by super radiance effects and Schwinger pair production, so it will stay neutral most of the time.
3) only super hard gamma rays have (to my limited knowledge) the short enough wavelength in order to scatter against such a tiny BH
By the 3 points above, it is unclear how to apply a back-force on the black hole so that a payload, comprising at least of the parabolic reflector, can be accelerated with it
are there any ideas out there about how to exert a force or moment on such a tiny black hole?