The reason being that I can make the search easier using one field rather than 12?
I can search for single months or multiple months (seasons, but not
If you wanted the "least code" then you create a field for each month allowing simple add, Edit, delete with no code. Then use a simple union query for all of the searching requiring little or no code.
Size would be irrelevant at 400 records or even 40,000 records.
The "best" most flexinble and efficient way is a normalized child table, which you still could design a simple form with check boxes to add delete child records.
Your solution seems to be neither the easiest or best approach, but you seem set on it and it will probably work fine. Seems unnecessarily kludgy. A solution without a problem.