Publish more in less cited journals, or publish less in more cited journals?
Actually, high impact journals get that way from the quality of the papers in them, not the other way around. So, I'd suggest that you look at it a bit differently. 

Write as much as you can based on your research. Make the papers as high quality as you are able, with new and interesting results. 

Publish them in the "best" journals that will accept them, but "best" means the most appropriate for the subject matter as much as anything. 

If you get rejected somewhere, revise and send the paper out again, perhaps to a less prestigious journal. 

Over time you will have a "mixed" portfolio. But you will have a good portfolio if you keep at it. 

Keep a lot of irons in the fire. You will probably spend the bulk of your effort at one project at a time, but keep notes on other ideas that arise along the way and outline new potential publications as you have the time. If you get stuck on your main project, pick up one of the others. 

No, the answer doesn't change. In fact it is the way to get, successfully, to the later stage.