I'm considering buying an external blu ray drive.
Is there one that's especially well-suited to dumping?

To dump CD based games with audio tracks I wouldn't suggest any modern drive. They usually lack of overreading capability.

Anyway as dumping drive, I would prefer any Lite-On drive, Mediatek based, rather a Hitachi-LG drive, Renesas chipset.

And I would consider the option of make external a decent internal drive, through a SATA+PATA to USB adapter.

On semi-vacation. MSF/AMSF to LBA/offset and viceversa calculator: link
To write properly occidental characters contained in japanese titles: screenshot
Spaces must be the fullwidth variant: link / screenshot