TW of our 1475 (Dry TW 250) with similar storage configuration as the 1575 is 440 camp ready with a full 6 gal WH which is at the back of the TT lightening the tongue. Empty the WH and it would be at 450+. Those #s with a GRP 24 Batt.
If their was any issues with tongue weight on a 1575 the members of Lance Owners of America forum would be all over it. They are a feisty bunch I assure you.
OP: If you like the 1575 it would make a great choice. Owners on LOA seem very pleased with it. We almost went with a 1575 but I didn't want a slide and the DW LOVES the chairs instead of a dinette.
Check'em out. http://www.lanceowners.org