Need to know weck jar size please

In the recipe headnote, the author states she is using two 7-ounce Weck tulip jars. A judicious search at an online retailer points to Weck Model 762:

https://www.amazon.com/Tulip-Jelly-Glass-Rings-Clamps/dp/B00F739OFC/

which is 8 ounces when filled to the rim (which the author is not doing here). Looking at the product photos, the jar's stated capacity is 220 mL. That makes sense since 7 ounces is just under 200 mL.

Best of luck.
Best of luck.

Guessing from the recipe yield (1 1/2 cups), you'll need minimum 10 oz or 300ml.
Safer still to use something like 500 ml, which will give you some space for stirring the mixture and in case your batch makes a little more.