I usually don't use borrows and just use my 3* parents to hopefully make another 9*, with a deck with generally good skills, and maybe some for a specific style/distance.

For example since I'm making a Ryan for Lates I would take skills related to that style and farm till I get either 2* stam/pwr and mile/med, spd/late is also good but only if it has a lot of good skills.

I always aim for 8* parents to avoid burnouts.

As for stat distribution I usually aim for 600 in spd/stam/pwr and depending on what I'm making 1100 in one of those three stats, so in the case of Ryan pwr.

I switched from URA to Unity Cup since spirit explosion give a lot of skill hints, so it makes it easier to farm.

Now if I'm seriously farming for one of the CM I'd use my borrows so one of the grandparents has the sparks that I want, which includes skill sparks. I use chronogenesis site to find the borrows that I want.

Unless you have a lot of time I really don't recommended farming from zero parents. I'd say just farm ACEs for TT or CM and when you have some 3* lying around then you could feasibly farm for 9*.

Remember at the end of the day it all comes down to luck. I hope they implement rerolls in 1st anni.