Hi,
I dont know if i can help you, but here is how the SMD-300 is jumpered when its used as an internal drive in Amiga 500:
There are 2 jumpers: nr 2-3 and 12-13
(With pin 1 on the lower left and pin 14 on the top right)
I am not sure however, if this drive is compatible with Amiga 1200?
And i think also there are difference between the Amigatech and the Commorore mainboards.
It sure is not easy with all the different drives in Amiga:-)
Maybe someone else knows more?