关于申请ＧＣ的招聘广告

1 and 3. if it is RIR, it should be in 6 month before you submit your ETA-750A/B form. at least 3 ads, which 2 in newspaper,1 in web. also one internal ad in your boss office. if your job need master degree, it is better to have ad in professional journal.
2.I don't think so. but it is either your real job requirment or your lawyer could write it.
4.I got a lot of information from hooyou.com.and also
http://www.ows.doleta.gov/foreign/times.asp
5.before your ad, should ask form prevailing wage from SESA. in TX, it is called TWA(texas workforce admi).they will decide how much of the salary should be after you get green card.then maybe you have to decide it is EB-2 or EB-3 application based on prevailing wage.
I only know RIR in Texas, not sure your region.
But GOOD LUCK!