Couple of thoughts…
Your lease partner seems to have the impression if the GREEN horse is a bit speedy over fences, It’s a Jumper. NO ITs NOT. It a Green horse that needs a quiet ride and to LEARN to relax and adjust their pace. That’s why many successful Jumpers spend some time in the Hunters and even if they don’t show there, they work very hard on that skill set at home before they ever see a show jump course. They start by ignoring the time factor until the horse is relaxed, attentive and adjustable.
Your lease partner also has only ridden WBs and these are generally “kick along” rides, you need a lot of leg and need to sit into them to drive them and keep them ahead of that leg. Your mare is a “pull back” or " steadying" ride by nature, you sit into her and drive, she’ll be in tne next County, likely sans rider. This gal needs to learn to “sit chilly”, you need to discuss this with your trainer, hopefully she can teach that. Truth is your mare is speedy with your lease partner because lease partner does not know how to ride her and gets her all lit up. She’ll be too speedy in the Jumper ring too, run past distances, blow the corners and tight turns, get rails and still not make the time despite galloping faster.
This, again, is a reason to have a sit down meeting, It’s your horse and you get to choose…and if Jumper rider/trainers of global fame start with rideability, adjustability and relaxation…i.e Dressage flatwork and the Hunter skill set? Suspect that would be the way to start. Maybe she’ll be happier in the Jumpers but AFTER she gets completely broke. Not “she’s too fast for Hunters so we will go Jumpers”. Please don’t. It’s not your issue if lease partner can’t ride her, that’s trainers job to fix.
One other much more minor point, you will be paying double the drug fees at a USEF rated unless something has changed drastically. One for the State of California ( which has required random drug testing at ALL horse competitions since around 1970) and one for USEF, they have slightly different standards, different testers, impose their own fines and use different labs. Non rated Schooling show is not subject to USEF testing so no USEF testing fee, Know it’s just a drop in tne bucket but there’s only so much room in that bucket, and yours is a small one.
Really need to sit down together and work all this out, there are some challenges that need to be addressed or they will cause drama and possibly conflict down tne road. I hope Trainer shared the fact the young, green TB needs a completely different ride then an older, BTDT WB. That can be dealt with but needs to be acknowledged by all parties.
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