Hi---Here is a suggestion. Go to the hardware store and find the vinyl tubing. Ace Hardware and most hardware stores have rolls of clear vinyl/rubber tubing different sizes. Bring your siphon and tubing along. Match tube end with something that is very close to your tubing , buy more than you needThanks...I'm an artist but work for the gubbmit...gotta eat! And yeah, those super long extensions are a PITA...I figured the 30 would at least keep the bottom of my hands dry. But no...damn hose is too short for a bucket drain and a long extension hose kills the gravity in the siphon. Worse, if I bend the tube too far it crimps the hose. That's why I ended up getting the electric vaccum. Now if I'm doing a partial water change and wait for the level to be lower, the siphon is workable. But at full tank? No way, I don't care what those UTubers show.
(Premeasure at home). It's cheap, less than a dollar a foot here. Then go a size or so up that will squeeze over your tubing. Buy a foot of that. Be sure it fits over your new tubing too. At home make sure ends of same size tubing is even. Slip the larger tube, (sleeve) over one tube end. Butt the same size tubes together and pull the sleeve over the second tube so it covers both smaller tubes equal distance. I found it makes a tight seal. Then gradually cut the longer new tube to where it works proper.
Or if possible pull the nipple of the vaccum chamber off from the tubing and buy some tubing that fits the vaccum chamber, and have it cut to the length (longer) you need. Make sure your other attachments can be made to fit.
What type of art?