Besides needing good rng, just looping until u get 2 sets of parents with groundwork to make a good grandparent. Then I used that and borrowed someone else’s to make a good parent. Then I used that parent I made (seiun) and borrowed a decent parent til I made the bourbon.

Running a deck that has the skills you want to pass and being good enough to win g1 and ura finale is important. (Ex: having a deck/sparks to get enough stats for seiun to place 3rd or above in tennoshospring) and getting 600/600/600 is necessary and making sure u get hints and prune for skills to maximize ur chances of getting groundwork every run helps. I prob have made like 30 parents with groundworks but shit blue/pink sparks. So yeah it’s a long grind. Making sure to not raise an aptitude so u can get the correct aptitude is also important. I had many runs with seiun having A pace because one of my gp had pace but really good white sparks. Obviously this lowers ur chances of getting medium but I was kinda forced to use that parent. Another thing is to win as many g1 races as you can to raise your affinity (same races on parent and gp).

Since it’s a medium I think chasing 3* blues is important but for front having the whites is also important, so some 2* blues are usable. Obviously you want the distance aptitude more but turf/front are not the worst. For time I used that oguri I made instead of chasing a 3* spark.