Is it that ...easy?
Yes it is:
- remove one of the floppy drives (*0)
- attach its ribbon connector to the SD HxC (*1)
- attach its power connector to the SD HxC (*2)
Ready.
But... in practice:
- (*0) depending on the drive you have removed (1 or 2), you have to set the J3 jumper of the SD HxC accordingly
- (*1) you have to find/build a cable adapter for connecting the ribbon cable. The SD HxC needs a 34 pin 3.5 connector, while the original connector of the EII is a 34 pin 5.25 connector. If you solve the problem by using a new standard floppy drive ribbon cable (which often has both types of connectors for at least 2 drives), you will have to set the J3 jumper of the SD HxC correctly if you use the "twisted" side because standard EII cables are untwisted. Also, most of the time, these standard cables are too short for use in an EII... So this could become a challenge...
- (*2) to connect the power cable, you need an adapter cable too (5.25 power --> 3.5 power). Fortunately these are widely available in local computer stores and on the internet
- build a case for it so that it fits nicely in the 5.25 space (--> quite a lot of work, quite a challenge...)