The choice of the in-row LOB length affects the storage space used for the data pages, LOB pages, and the number of rows that can fit on a data page.
Specifying an in-row LOB length greater than the logical page size is ineffective, as only LOB values that are smaller than a page size are considered for in-row storage. Conversely, specifying a very small in-row LOB value may move very few LOB columns in-row, and not yield the potential savings in LOB storage space.
A typical in-row LOB length is somewhere between the range of the minimum data length of a LOB column and the logical page size. A large in-row length value may fill an entire data page with just one row, so a practical useful value lies close to the average data length of the off-row LOB column where the length is less than a page size.
The choice of the in-row LOB length can also potentially affect scan performance for queries that return large numbers of rows, and that do not reference LOB columns. If very few rows fit on the data page due to large in-row LOB values, then the number of data pages scanned might be very big, thereby slowing query responses.
Examine the data lengths in your tables to estimate the in-row LOB length so that more than just one or two rows fit on the page. Balance performance impacts against the reduced LOB storage.