I have not tried it, but if I had to resort to an RC for a taper it is what I would choose.

Pharmacologically, diazepam is a long-lasting [30 - 80 h] active benzodiazepine that metabolizes into the similarly potent and long-lasting [40 - 100+ hr?] desmethyldiazepam (also called nordazepam when sold as a pharmaceutical). This gives it its ideal taper agent properties because it lasts for multiple days.

Diclazepam should more properly be called chlorodiazepam. It seems to be a moderately long-lasting [30? - 80??? h] RC substance which is metabolized in vivo to chlorodesmethyldiazepam. That's also known as delorazepam - which is a long-lasting [50 - 100+ hr] benzodiazepine which is an approved drug in a lot of countries (it itself is metabolized into plain old lorazepam).

If you can tolerate lorazepam I suspect it would be a good taper drug. It's probably more hypnotic and less muscle relaxing than diazepam, but that's totally a guess.

Roche (makers of Valium) patented but never marketed chlorodiazepam. I don't know why.