If the metal parts in the carbs are good, why replace them with kits of unknown quality? They aren't that hard to clean, if they aren't corroded.
I have always used the Honda carb kits which I get for about $17-18 each. Has all the orings and gaskets for an overhaul and there is little question of them fitting properly.
If you follow the forums, you'll find varying results with Keyster kits, some like them, some don't, because the parts may not meet the same quality control as Honda. It's cheaper to sell parts if you skip the quality control inspection. I've yet to hear of an overhaul failure due to the use of Honda gasket kits. And, I don't like to do the job more than once?
Further, Honda produces parts while they are profitable and has a decent turnover. Think they will still offer parts when there is little demand? Something to think about...
Finally, isn't an overhauled set of carbs worth $80? If money is way tight, then contact Kevin400F, as I think he still sells the main jet orings individually.
Your call...
Cheers,