Dear AshMegJo, the first thing I would like to recommend is a shorter strand of beads. Since you are a beginner, and more accommodated to plugs, too long of a strand might feel uncomfortable.
Another thing you should look at are the spaces between the beads and how gradual is their increase. I wouldn't go for beads of the same size, since they tend to be larger and have big spaces between them, as well as a big ridge between the strand and the bead itself.
So, gradually increasing small-spaced or not-at-all spaced beads that are not too long. And definitely silicone.
I feel like the best option would be
this strand right here - it has a comfy handle and a very mild change of width. It works wonders if you want to use beads as they are meant to be used - for beading off, aka pulling the beads out on the edge of the climax.
If, on the other hand, you want more of a butt-plug-like experience, for beads to stay inside for some time, and only enjoy the texture whether than pulling out, I'd go for
for this option. A safe base and a modest size will make your wear super comfortable.
Hope this helps!