take a deeeep breath. you're learning something new like, every posting so of course you're changing your mind and needing to make adjustments. explain to your dad you found a solution that is UL approved (UL is the leader of product safety testing) and should not be of concern.
one thing i forgot to ask: what is the size of the area between the bars?
I actually don't even know... All I know that it's definitely smaller than 8.5", and that that size dome was maybeee an inch or so too big? So estimating somewhere between 6.5" to 7.5"