following just for your reference. don't "后来看到你写的K1和K3签证的信息,改变了主意.". all decision is yours
there are many things to consider other than several months processing time.
K1, need more proof at interview in Guangzhou. after come to USA, still need file I130. in another way: I130 is one of the step you have to go through.
for k1, most will get CR1 latter. this leave you i751 two year after.
K3, just check if the marriage is true and legal, your income is over 125% of the line. your I130 already approved.
many K3 directly get IR with no string attached.