When using triple detection, you do need to calibrate the detector response and determine the inter detector delay. This does require a standard of known molecular weight, but it can be 20,000 daltons or 200,000 daltons, it really doesn’t matter what it is. You do need to know the concentration and in the case of an RID the dn/dc, a UV detector the extinction coefficient. The Agilent GPC software does included a wizard which takes you through each step of the process.
Once this is done and the software has calculated the constants you can process your triple detection data. There is no need to calibrate the columns.
So it doesn’t really matter if your sample is 80,000 or 8,000,000.