[Check Point] Is it true only one Administrator can configure Security Gateway at one time?

So, our team consist of 5 person. We are going to deploy 3150 as our Management in HQ, and 14XX at our branch (over 400 devices).

1. I read that that only one Administrator can configure the Security Gateway at one time, is it true? (Source: http://ift.tt/2BqPr1c)

2. Can all 5 people configure the SG from Management simultaneously?

3. What would you recommend to me if you want to deploy all 400 devices faster?

I need some guidance. Thank you very much.