I gave up my first China game when the civil war happened, but came back for a second game and rode it out. My key advice would be to:
1) Have a fairly strong standing cavalry force built by the time the war starts. Cavalry is extra effective vs. rebel scum
2) Be prepared to give up territory -- If you try to play whack-a-mole with every revolt like you normally do, you'll only burn yourself out. Target only provinces of particular economic importance, or ones easily taken (clear terrain and weak rebel forces). Expect that you'll have a lot of cleaning up to do after the +20 curse is lifted.
An event some years into the war allows you to effectively enlist Manchu assistance to suppress the revolts, effectively changing your nationality to Manchu temporarily (and, I believe, recreating them if previously conquered). I chose to do so, and their army arrived in the nick of time to replace my depleted original force. If you prevail in this fashion, at the end of the 20 year interregnum you get to re-style yourself as the new and rightful "China", and get your old nationality back.
I believe you have the alternative choice of effectively alligning yourself with the southern rebels, but that leaves you militarily weaker, and faced with a fresh Manchu foe looking for a fight.
I enjoyed China a great deal, in spite of the dynasty change. You pretty much get to chose your own strategic direction, since none of your immediate neighbors is strong enough to pose much of a threat (except maybe the Manchus, if you don't beat them down quickly. Japan is militarily pretty tough, but is hard-pressed to sustain any overseas invasion). I ultimately controlled most of SE Asia, threw the Portugese out of Macao, had colonies in Borneo and Sumatra, and had staked claims to much of Siberia (Russia never really became much of a power)
