It sounds like this discussion has surpassed my knowledge on the topic but I would like to share some resources that provide more insight into how to convert illuminance to PAR for indoor applications. These sources demonstrate that 54 lux / 1 µmol m-2 s-1 as an appropriate conversion factor for sunlight and that PAR should be calculated daily. It seems like the individuals on this thread are beyond the simple conversion but I thought I would share for everyone’s consideration - hopefully its not too reductive!
Chun Liang Tan, Nyuk Hien Wong, Puay Yok Tan, Mirza Ismail, Ling Yan Wee, “Growth light provision for indoor greenery: A case study.” Energy and Buildings (2017) 144:207-217.
Ismail Tan, “The effects of urban forms on photosynthetically active radiation and urban greenery in a compact city”, Urban Ecosyst (2015) 18:937-961.
Brian Chabot, Thomas Jurik, Jean Chabot, “Influence of instantaneous and integrated light-flux density on leaf anatomy and photosynthesis,” American Journal of Botany (1979) 66:940-945.
Apogee Instruments, “Conversion – PPFD to Lux”, https://www.apogeeinstruments.com/conversion-ppfd-to-lux/, accessed Nov 15, 2018
Cycloptics, “PPFD Conversion Guide”, https://www.cycloptics.com/sites/default/files/Greenbeams%20PPFD%20Conversion%20Tables_0.pdf, accessed Nov 15, 2018