create a list from a table

At first glance i'd use Power Query (aka Get&Transform).

Creaty query from initial table,

Generate one more table which repeats each number from 1 to max possible that numer times (other words, one row for 1, two rows for 2, etc). Most probably could be generated with M script from the list;

Right join source table with the second one for LH;

Same for RH;

Generate required list string for both in new columns;

Remove in each all columns but size and list string;

Append one table to another;

Remove size column

Not sure right now about totals, perhaps one more intermediate table will be required.

Above is just an idea wich could be workable