I would also like to know if these would be as good or close to being as good as a 15 att SCG. My guess is no, but I'm not exactly sure...
It depends on your definition of 'close'to being good. Will these do the job for a small fraction of the price of a 15 Attack SCG? Yes. Is it the same? No. Probably worth 90m. Limiting a certain equip to one class will almost never equal out if you were to scroll an item for every class.
