A good rule of thumb with matching mares, is to always start with stallions on the LB. By using a stallion on the LBs, you know you are matching your mare to a stud that is strong himself, but also is producing good foals.
Some horses have good ratings and training, but just aren't good producers.
So for example, looking at your mare Rapid Power, her foal "Tiger Eye" was sired by a stud who never hit the SHLB, meanwhile her foal "Grey Skies" is sired by a ABLB stallion who is very high on his breed LB.
Looking at the two girls you have linked:
I would not expect anything good from Bold Endeavor. She is only up 2/6 on her wk4 and is sired by a EWW out of an EEE. She doesn't have a lot going for her that would show potential.
On the other hand, Blue Cyclone has some better signs of potential. Being up 4/6 on wk4 is good as well as being from a WWW x WWW cross with a SHLB stallion. However, being up none on wk8 is not a great sign as you ideally want equal to or better than their wk4 on a wk8. Honestly, I would not expect her to produce better than EEEs.
Continue to carefully watch Blue Cyclone's training to see if she better reveals weaknesses and strengths in her later weeks. Hopefully, she will show a strength that you can use when matching. She will likely do best with a stallion that is all up wk4, 8, and at least up Mv & Int in wk11.
One thing I stress a lot with breeding for LB, is making sure you're investing in horses that will actually progress your stable vs keeping it stagnant.
When adding mares to your stable, look for ones with good training (the more up wk4, 7, 8, 11, & 12 the better) with parents that have good production. Ideally out of a high LB stallion and even better if out of an LB dam. Sometimes you can scoop up an EEE mare for cheap who is very strong. I've bred high LB horses out of EEEs who seem to have just fallen "short" of being a better rating.
Then when breeding, breed your mare to the highest LB stallion who matches her that you can afford. :)
If you have any questions, my inbox is always open!
Morning Drizzle, but Clearing later
