Droll Yankees New Generation Finch Flocker Birdfeeder

Is there a dome that will fit this?

I ve had this fweder up for weeks and no birds. Birds eat at my other feeders. Worried the holes are too small?

Because the feeder is so long, is there a way to open the bottom so that it can be cleaned? I have heard complaints that it is too long to clean.

Is this strictly for nyger/thistle, or can you put hearts of sunflower seed in it?