You could make a barrel 5x5 if you chose too.

A Rhombic dodecahedron 5x5 isn't a hard mod. Belive me. But if I don't convince you enough, barrell 5x5, wall 5x5, or a 5x5x3. Just search my topic about my 5x5x3 here on the puzzle mod section. I can't give you the link because I'm using mobile. Goodluck!

5x5 Cuboctahedron! There aren't enough of those.

First of all, please keep your messages at a reasonable SIZE and COLOR.
We can read what you say nomatter what, dont worry
So next time just use the default settings please.

Next for a suggestion I would say a Sphere 5x5x5. I haven't made this mod myself, but I don't think it is too hard.
Just look up Tony's Octa Ball - tutorial on youtube. The procedure must be very much alike.
To sum it up quickly, use sand paper or a dremel. Work your way as you go, dont make an exact plan. Work on the puzzle assembled, dont take it appart.
When you have taken some material off, then simply scramble the puzzle around and continue.

It would be ideel if you filled every cubie up before you start sanding down. But you can also fill them up after you finish the ball shape.

Just a suggestion

I would say for a beginner the best mod would be a cuboctahedron. However there are many other cool mods, such as a sphere, a barrel and a hexagonal dipyramid.

NOTE TO EVERYONE (i forgot to mention it) I DO NOT HAVE A DREMEL and I think Im gonna make a barrel, burr cubr or a wall cube