Mixing clonazepam + Valium is it okay

We are trying to make a switch from clonazepam 0.24 mg to Valium  approximately 5 mg. This is being done by liquid micro taper; I am a chemist so this is not complicated for me.

We are doing two 0.12mg doses , each dose has a mixture of 65% clonazepam + 35% Valium. The percentages will change  by increasing the Valium and reducing the clonazepam until  we are at a 100% Valium (5 mg), then start her taper.

Is there a problem mixing the valium + clonazepam?

The Ashton manual dose not combine but instead has a valium  dose and a separate clonazepam dose.

The problem we are having is withdrawal symptoms as we reduce the clonazepam.

We need feedback

Thanks