Multiplex FunCub

Here's how I ended up attaching the floats.
This photo is the front and uses the stock landing gear and wheel collars to keep it in place.
The second photo is the rear attachment and will be left in place on the floats when switching between wheels and floats.

In the first photo it looks like the inside collar is only used for attaching wheels?

Right. I've used thread lock on the inside one so it stays put. The gear is flexible enough to slide the axle either way but doing so will change the angle of attack of the wing in relation to the floats. Where it's set now gives about 5 degrees I think. A test flight or two will see if any change is needed.
School will be out soon for the holidays for a couple weeks so I'll take it down to the ball field and give her a test flight then (with wheels). Testing with the floats may have to wait for a while.

One last photo.

Terrific job Bill!  Congratulations!  Your paint and details came out really nice.

Thanks John, now to see if she floats and flies. 

It does fly. 
With flaps down and into the wind I think it would be easy to walk faster than it flies.
It handles really nice on grass with the big ole wheels that came with it, not so well on hard surface though and I had read that would be the case.
Next is to find a pond and see how she sits on her floats.

Congratulations Bill!  Is it a little bouncy on the hard surface?  Any photos or video?

I went out by myself so no video or photos yet. 
The wire landing gear has a lot of flex and with the big wheels it doesn't do to well on a hard surface take off.
Take off on grass it's pretty sweet, the big wheels roll along nicely and the gear absorbs the bumps.
The plane is pretty floaty when landing but with half flaps I could stick almost every landing without a bounce back into the air. 

Sounds like you had a good day.

I read a funny expression a couple weeks ago: "Take off optional, landings mandatory."

Do you have water near you to test the floats?  Where do you go for that?  Golden Child told me his club will have the "Float-Fly" again this year.

It was a fun outing.
Well, I can test to see if the plane on floats will actually float properly about any where big enough to sit the plane in. That's the first step, if it isn't to tail heavy on the water I'm sure it will handle nicely. There are not many good places to fly off water near by though.

I don't think we have any water large enough for planes close by.  Golden Child's club usually has the float-fly on lake Selmac here (green arrow):

https://maps.google.com/maps?q=42.258103,-123.582477&ll=42.258858,-123.581085&spn=0.029126,0.046434&num=1&t=h&z=15

I got around to checking balance on the water and she sits very nice. Can't wait to give it a off the water now.