1) I agree. You have to try before you buy.

2) Yes. Many!!! 8thstreet music, they sell it for good price. Also George Kay is very respected and knowledgable dealer. You will find him in the arranger keyboard forum.

3) WK6 is supposedly identical to SK760. The difference is that WK6 has built in speakers while SK760 has 76 keys.

I hope this helps