Why are you even running biscuit mounts? Spool mounts win.
This should solve your issue, flat out. It might be that you're breaking mounts because there's another issue, but I'm not liking those cantilevered brackets in any way.
This has all been a learning experience, and with the limited space and experience I went with the biscuit mounts. At the time I didn't realize I would be breaking them so often. However I agree with the brackets, hence why I'm asking about whether or not I'm asking for trouble.