Wire or Dowel  

Dowels
Look nice, but the Eiffel may be sturdier.

More
A couple more pictures

/i think the padded shells lo...
/i think the padded shells look best on an H base. But if I had to chose from, I'd go Eiffel

I do have
The original "h" bases too.... humm more options...

Jesgord +1
The upholstered side shells look funny to me on anything but contract or H-bases. And, for the record, I don't like the "wall-saver" H-bases on either upholstered or non.

Agree
I agree that the padded ones look funny with anything but the h-base, the aluminum swivel base, or the stacking base. But if you have to put a eiffel base, please make it zinc.

Normally I prefer the dowel...
Normally I prefer the dowel but with the vinyl chairs I'd go with H or Eiffel.

In my opinion
a white La Fonda base would suit these blue and white shells the best. But if you must choose between Eiffel, dowel or H, go for the H base.

A quick collage just to get the idea.

Nice idea
But white La Fonda bases will be difficult to find. May be easier in Europe.

The La Fonda
The Lafonda base does look really good. It looks taller to me though. The H bases I have are in need of some cleaning. I'm going to see if I can find some tips on cleaning them here on the forum. If I can get one cleaned up I'll post a picture of it mounted on the chair.

H-base
Steel wool and WD-40 usually does a decent enough job. The base won't be super shiny though, if that's what you're after.
The La Fonda base is a bit taller than the standard H base, if I recall correctly.

H base
Here is a couple of pictures of the un cleaned H style base if anyone is still looking at this thread.....
Any thoughts?

Yup
While the H-base may not seem exciting, they now look like how they were intended to look. Don't go crazy trying to clean the zinc. The plating is thin and chips off easily. I protect my bases with a little car wax.