I would like to gain an insight on the various methods of measuring biomass and growth of Aspergillus oryzae, which you have personally tried and would gladly recommend.
check out these publications on Aspergillus niger which could help you in finding a suitable protocol. Try gravimetric dry cell weight estimation via filtration or centrifugation:
https://pubmed.ncbi.nlm.nih.gov/20502893/
https://pubmed.ncbi.nlm.nih.gov/19953678/
Article Integration of in vivo and in silico metabolic fluxes for im...
You can even customize the morphology by adding microparticles:
Article Customization of Aspergillus niger Morphology Through Additi...