And, wow, lol. That's pretty high. That sure if possible, but I mean... it'll take a while to hit (Especially on a game cart xD). Like, a really long time, since the most you can advance by (In HGSS) is 2. I think I have a solution, though, since I had something similar with my abused ID/SID but I was able to lower the frame.
Try searching for your shiny spread in RNG Reporter/PokeRNG, but make the delay range much wider. That way, you might fin your seed on a higher delay, with a lower frame. That worked for me, so try it and see what happens.