You may be ahead of yourself....on paper, you won't actually get to the top of CX doing what you described if you're only doing it for 9 months. It will take you considerably longer to get to the top of CX's program than you or SFO_FT may be expecting. Long story short, you'll need to do 210k club miles before getting DM (not 120k as it may look at first glance, or 100k for UA 1k or AA EXP). That's because they reset the tiers as you progress. So you do 30k, reset to zero as Silver. Then you do 60k, reset to zero as Gold. Then you finally do the 120k that gets you DM. You probably can get SL comped to you have an impressive recent flying record, but you still won't be DM until you're 180k miles in. So say you get 18k miles for a round-trip in J ORD-HKG, you may not actually even get to DM with 9 round trips.

If you're flying full F fares I suspect CX is going to flag you rather quickly as someone they'd like to keep around so you'll receive excellent service regardless, and DM is going to be moot because you're always in F. So I guess you gotta be honest with yourself and know what split you're actually going to be doing J versus F (I presume these are all round-trips, not part of AONE or DONE tix), how many trips you actually will do, and when you will stop. Because if you're doing a lot of J, I think you're going to be disappointed that you probably won't make DM.