text field

IDS 9.21. We are in the process of making a change in a heavy insert table. This table gets lot of inserts. A row , after getting inserted, is read and updated for next few minutes by another process. After that the row has no utility left and is deleted at the end of the day. One of the columns in the table is a VARCHAR column. This column now will store additional information which can run upto 20K in length. This means both VARCHAR and LVARCHAR can not store that size of information. My main concern is the performance penalty during insert if the column is changed to a text field. Which is the best way to store this field. TEXT in TABLE or TEXT in blobspace. I know that TEXT in blobspace bypasses buffers. So that would mean that every insert will result in more disk write. OTOH text in table may consume lot of buffers, even though it will avoid immediate disk write. TIA.