Sedo Parking -- 2 Simple Questions

[ImageAuthors]

2 very basic questions about Sedo Parking:

(1) Should the master keyword be a single term or several terms separated by commas?

(2) If the domain name isn't English, should I choose relevant keywords in English (with a high CPC) or keywords from the native language (with a moderate or low CPC)?

Any advice from experienced domainers would be very much appreciated. I'm new to the business as of last summer, and now I've got thousands of domains parked without any keyword optimization whatsoever. So I guess I have a third question:

(3) How much difference do you guys see in earnings with or without keyword optimization?

Thanks in advance!