VARCHAR vs LONGVARCHAR vs CLOB

Hi all,
while looking further into migration to 4.2 I noticed my model has several DbAttributes defined as CLOBs, leftovers from our previous database (Informix).

Since we have migrated to Postgres and these columns are now just regular varchar/text columns, I'm going to redefine them in the model as such. So I'm wondering, mainly out of curiosity; is there any difference in how fields of type VARCHAR and LONGVARCHAR are handled WRT Cayenne or should I just define everything as VARCHAR and forget about it?

Cheers,
- hugi