I think you've got the wrong person, because I haven't done ANY HG/SS breeds at all :/ the cyndaquils I posted in DMP are the ones you get from elm, and all of the BPs I've done have been in DPPt
However, if it works as I believe it does, in DPPt you would do the 10 flips to check your seed, 8 more as required by shiny finder. But I'm not certain what the "-1" means. It could mean don't do any taps, but flip to the happiness checker app, which is a RNG advancement of 12. If that's what it means, then your egg would be #31, since the RNG was advanced 30 times (10 + 8 + 12)
Sorry I couldn't help more, but I haven't done any HG/SS stuff yet (besides starters, which doesn't use elm calls/IRNG stuff)