[Deebo]

I would go with the coals, you can easily build a device like a stump burner, check you tube, and then stop the process, only need an air source and some sheet metal. If you mess up, just try again.
I can see some off my cousins and I "plunge cutting a skill saw" to get the same results, but I would NOT suggest it. But then again, me and my cousins never were too smart............

 

[Deebo]

Please, remember you are going to have to register that "cigarrette and ash holding device" with the federal governement, and becouse it is considered a flammable material, you have to have it registered and insured in your name, with a blood a nd dna sample provided... Also, since you are planning to repurpose and alter the original design, you will have to be federeally inspected prior to use, and annually taxed on said devise......
Actually, I think I will try one, would look awesome by my fire pit..