HELP! multiple entry H1B visa

My visa history is F2, F1, H1B. I came to the states 5 years ago. Never left since then. I am currently applying for LC/RIR.

For business reason, I may need go back to China with my co-workers. It seems a good idea to get a multiple entry H1B visa from a US consulate in Canada. So I like to have some suggestions about:

1) How risky it would be?
2) If I were rejected, would I also lose the chance to get back to US from Canada?
3) My company is in semiconductor industry, and I am a software engineer. Am I subject to security check?

Thanks a lot. I appreciate it