I bought one of older models that were on eBay for $26 (non adjustable position) to use on a 10wx16h column vase Iím going to set up for mini tank at my work desk.
Only going to do some crypts in bottom, some moss/fissidens mounted to branches mid column and hydrocotyle Japan tied at surface for plants though.
From what Iíve seen, at 6.5w should deliver med-low light in most 5gal or shorter tanks. Plugging mine in, color rendering and balance seems very good. Also, on mine power adapter and light are connected via 2.1x5.5 dc plug so inserting a dc digital timer/dimmer should be easy.
Iíd say go for it your just doing java fern, moss, Anubias/buce or hygro compacta in that depth tank. Could probably do some of the easier Ludwigia species. Growth wonít be bombastically fast but slow and steady.