Hi Martijn,

1) Yes, the GW/BSE oscillator strength and other properties are meaningful. Use them just like the TD-DFT ones. Actually, the oscillator strengths seem to be rather good (see J. Chem. Theory Comput. 2016, 12, 8, 3969–3981; also we found the lifetimes in 2c GW/BSE calculations to be often better than their TD-DFT counterparts). However, GW/BSE oscillator strengthts do not obey the sum rules as TD-DFT (so velocity/length representations will not coincide for a complete basis set), if one is very strict about these things.

2) As Uwe said, you can visualize NTOs just like TD-DFT using the proper program, there select the mos / dftnto menu. the dftnto menu will actually recognize the $bse flag and report something like "found $bse flag, assuming BSE response calculation". The transition density of JCC 2017, 38, 383 can be obtained from the "panama" script, which should also be compatible with GW/BSE (we recommend the use of NTOs though)

All the best

Christof