You won't need to extend the fixing time, just go with the recommended time for the dilution you are using.
I'd recommend against agitating like crazy, unless you want possible uneven development as a feature of the prints. If you want to increase the contrast extend the (assessed) development time instead.
I'm sure others will give further suggestions for you - like the results of the film, always wondered how they'd look and the subject suits it really well.
You won't need to extend the fixing time, just go with the recommended time for the dilution you are using.
I'd recommend against agitating like crazy, unless you want possible uneven development as a feature of the prints. If you want to increase the contrast extend the (assessed) development time instead.
I'm sure others will give further suggestions for you - like the results of the film, always wondered how they'd look and the subject suits it really well.