Need 18mm knot

I'm restoring an old brush my grandparents gave me. I've removed the old black-badger knot, sanded out the inside and all I need now is a knot. I'm not planning on rehabbing the handle. I kind of like the well-used look it has. I will put a light clear coat on it though to protect the areas where the paint has worn off.

So I'm looking for an 18mm badger knot. The Golden Nib has one in best badger but they've been sold out for a while now. I don't want to get their 18mm silvertip because it's my first restore and I don't want to ruin a silvertip if I mess it up. Plus I have a strict budget for this in the form of a Visa gift card ($20). The silvertip is $25 so it's out anyway.

So does anyone have any ideas of places to get an 18mm badger knot under $20 BESIDES the golden nib?

I have a 19mm black badger hair knot, it was supposed to be 18mm but it is a hair large.

I have an extra black badger 17 mm knot I didn't use with a Plisson restoration. Loft is 50 mm.

Do you want to stick with a black badger? If not I have a 20mm TGN finest and it is my favorite knot. They have a 18mm for $16.95.

18mm Finest Badger Hair [18- FINEST] - $16.95 : Fountain Pen parts - NIBS, - Wholesale Fountain Pen Ink - Golden Nib AZ