Doh.... I was thinking regular SD cards.

The only time I have used them was with an adapter so using one straight should not be a problem.

Looking at the pin outs between the two it appears pin 9 has been dropped and pin 1 is not used on the micros. Pin 2 on the micro is the same as pin 1 on the full size, I think. Just compare the pin names and functions between the two.

SPI.... That is what SDFS uses. The only option it hardware SPI or not. Testing for speed between the two I have not seen a difference. Hardware SPI on the chip I use is also one of the USART pins so I have been using software SPI.