Canning - old school
A bushel of tomatoes weighs between 50-60 pounds. A peck or 8 qt. basket weighs 12-15 pounds. So a 11 qt basket is somewhere in between. https://www.kn-eat.org/F2S/F2S_Docs/Guidance/Volume_Conversion_Chart.pdf Another reference is http://www.pickyourown.org/info.htm.
The weight varies with the size of the tomatoes.
Make sure you are using a tested recipe for your chili sauce. If your grandmothers recipe uses meat, peppers, onions, or other low acid vegetables it will need to be pressure canned or frozen. Pressure canning will need to be for the longest processing time of a separate ingredient. https://nchfp.uga.edu/publications/uga/uga_can_tom.pdf.