Tfkaudio,
Blackbird HO MC is rated at 2.5mv output so you don't have to restrict its use with only MM phono stage's 47kohm. Since the Blackbird is a MC cartridge (at 2.5mv) I believe you can match with any MC phono stage to get more flexibility in terms of gain and loading settings. 54db gain and 500ohm loading are only a starting point. You can increase or decrease the gain but keep the loading below 500ohm for better sound in my opinion.
