I see there so many elbows and o-rings... :-(
Could you please put a link and/or image of the elbows and o-rings you're referring to? Thanks.
You need to go to an online parts web site - eg. Partzilla - and search through various "fiches", which are the blow up pictures of various ST components, all with the little numbers indicating the parts involved. If you have the carbs out now, by having a good look in that space, you should be able to identify whatever parts you think you need from those fiche pictures. The elbows, o-rings and hoses are under the cylinder head fiche. Once you look around the various fiche headings, you will find everything you may need for your bike.
This will save you, and everybody here, a lot of time going back and forth with the posts. Not that we aren't here to assist in some decisions, or advice, but learning how to use those fiches is mainly for your own benefit.
Yes, you could use a bit of foam filter from a lawnmower, but you'd likely have to go out and buy that too, so you might as well, for the little it costs for OEM, buy it along with whatever other parts you need to order.
Just a suggestion, because it sounds like you are heading into expensive territory asking a shop to rebuild your carbs, which may not be necessary. Maybe you should PM (private message) to John O. and see when and if he could make a trip to assist you.