Have you ever used a do-it-yourself repair kit for cultured marble?

[Belle5]

I am wondering how doable this is. We have three sets of bathroom/ counter sinks and also a garden tub that could use crack-patching/repair so that they don't need to be replaced. If this actually works, it would save us a ton of money. We are trying to get the house ready to sell and the costs are pretty staggering getting it ready to go...(carpet, paint, other repairs...)

I am concerned about our "white" cultured marble being patched with a brighter white-white and the repairs showing up. There is a $20 tinting kit that might be useful for making it a duller white...

Anyway...any experience with this?

 

[Belle5]

Anyone?