yes, if you have several used Chinese visa in your passport, it helps. The longest stay duration of a single entry tourist visa is 30 days, if you get a double entry, 30 days stay duration each stay.

Well single entry you can get for 3 months with 30 days duration same with double entry because its not easy for you to get 90 days duration or 180 days because now its not that easy to get a visa to china now matter how many chinese visas you got . But easy way is if your working or married to chinese still that she must have a good work if you dont have anything to prove . I have 6 months duration visa and I can reapply again for another 6 months too for me is easy .