Holley quick change float bowls?

Anyone use these?

Carburetor Fuel Bowls - Quick-Change Jet Provisions


I like the idea but wonder about how well it actually works? Seems like the jets would just fall into the bowl and I'd ha e to remove the bowl anyway? Seeing as the jets are non magnetic what keeps them from just falling off the tool?

For me it's a 200 dollar investment on something that may just be a gimmick?

I have a feeling on my new super top secret project that I will be changing jets a LOT, so if these work I'm ok with spending the cash but seeing as I'm trying to make lots of power with little cash I cant just go buying what ever I want.....

Thanks for your time and advice.