Adjustable dumbells instead of Chi Ishi

I’ve been trying to practice the Hojo Undo exercises as part of my karate training. I’ve been following a book (Art of Hojo Undo) for this and have found it useful especially the makiwara and nigiri game.

I had a question about the chi ishi (weighted levers). The book recommends building them using cement and a wooden dowel. However, I found that using an adjustable dumbbell with weights only on one side was a simpler construction. The difference I can think of is that dowel (which in this case would be a dumbbell bar) would be heavy itself. This would change the weight distribution of the tool.

I wanted to know if people here use this and whether my concern about the weight distribution is genuine or whether I can just go ahead and continue using this.