If they aren't in GEDCOM format, so much the better. I'm creating roughly 50 profiles a week for various projects. I usually start by looking the person up on Find-a-grave or in a death index (not SSDI because they don't give death locations)--anywhere that has birth and death dates. I use Wikitree-X to create the profile from there, which takes a few seconds. Then I search Familysearch to add sources, sometimes using the RootSearch shortcut that lets me search Ancestry or Family Search right from Wikitree. If I had a spreadsheet, I'd probably convert it to a Wiki Table, stick it on a free space page, and then work my way through the names. It doesn't take long to create a profile--the research is what takes awhile. But if it seems daunting, and if you already have done scads of research, then add as many as you're allowed to by importing your GEDCOM. No big deal--whatever works best for you.