I would suggest not to bring all the files into one single AC file.
Another way to avoid laaarge files is to convert each IFC file into a PLN or a MOD file, and then Hotlink one by one to your Architectural or "Main" file.
In this way, in the future you can also replace or update the "others" files without repeating the process, only updating the hotlinks.
... my 2 cents.
P.S. Have you used profiled walls/beams/columns? did you experience problems with IFC translations of the profiles?
Regards
Nando Mogollon
Director @ BuilDigital
nando@buildigital.com.au
Using, Archicad Latest AU and INT. Revit Latest (have to keep comparing notes)
More and more... IFC.js, IFCOpenShell
All things Solibri and BIMCollab