Just stop creating your own techniques.
Use a very well known, common and functional secret sharing scheme, such as Shamir's (SSS).

Doing your own crypto always fails. Whether encryption or something else doesn't matter.
Professionals in the field of crypto already created several good secret sharing schemes.

You don't have to use Shamir'r secret sharing scheme which is based on polynomial interpolation.
There are other gemoetric schemes or schemes based on the chinese remainder theorem available.

Just use a scheme made and approved by cryptographer.

Don't do your own crypto!