Voltaire’s are awesome!!! I love my Antares spooner though!
Im not sure what you mean by flexible but, I have an Antares Spooner and I love it! It fits almost every horse I have put it on (9/10 infact!) I highly recommend any saddle from Antares, this is my 2nd saddle from them and they have been amazing to deal with!
Check with your local saddle rep. I recommend voltaire for their incredible quality and consumer service. They will be able to help you find the right saddle for your horse