Hi.
Or start a third or fourth thread asking the same question
^This
Starting multiple threads on the same subject is considered normal and is thus accepted behaviour in certain forums, but it's better to stick to one and bump it (sparingly) if necessary.
As for Your question about a F# capable amp, the already suggested headphone-amp is the best solution by far if just practising is the immediate need.
If You want something "nicer", a pre-amp and heaphones would be the next logical step.
If You want a gig-spl capable rig for F# tuned bass, 1KW is IME the very minimum and requires a very efficient speaker system. Add a zero to Your budget if that's your goal.
That said I practise with a SWR WM10, and have even used that as a monitor live when playing in a small bar and a hefty PA.
But, You have to be
VERY CAREFUL since a ported cab doesn't offer the driver
any suspension below the tuning frequency and over-excursion happens very, very fast.
Less than 10W at sub 30Hz frequencies can blow even the sturdiest of MI driver(s) so better to roll off the lows and to consentrate on the harmonics.
Regards
Sam