It depends......what your final product will be has a great deal to do with what type of scanning you need to do.
If you can scan up to an 8 x 10 print, you won't need to fuss around with resolutions assuming you wan tan 8x 10 output. This will give you the most options for your final output, be it a digital negative or a scan to a web site. That's one good thing.
It is written by many "experts" that one can't scan a negative on a flatbed scanner (even with an adapter.) without losing quality. I do 4x5 negs on a flatbed scanner (with adapter)and they seen to look OK when I finally get them into 8x 10 digital negatives.
The most important question to answer is the first, "What is the final size and media to come from the scan."
It is more important to use the scanner you have wisely than anything else. Calibration is very important either way you go.