I did a search on window fuzzies and found people have said use OE type fuzzies.
Is there a perticular brand that fits and functions better than others?

Also I want to test fit these before my car gets painted. Is it possible to do this with out damaging them to get them off or should I just wait until after the car is painted?

Get PUI fuzzies ............ test fit ....just check to see if clips line up with your old ones .... there are 2 versions of 66 fuzzies ,call PUI and have one of your old ones to compare and get proper pn .......

I got the PUI fuzzies and all fit except the outside of the doors. One clip was in the wrong place. Called PUI and they told me that there were two different styles.

Whish I knew that before I ordered mine.

I dont have my old fuzzies.
Any other way to tell which ones I need?

I don't think GM had two different door styles in 66. Wonder why there are different style fuzzies(clip placement).

The problem I had was only with the outside fuzzies for the doors. all the other clips were in the right place. On my outside doors all the slots for the clips were located exactly 4 1/2" apart. I think you have to check the distance between the slots that the clips go into and have the vender verify their location on the fuzzies you order. The PUI rep said I needed Part # O202-1A. But maybe your using Repops or TWI two other manufactures of the window felts.

Doesn't seem logical to me either that there were two different doors. But PUI rep RON FOX said they had two different sets of felts for 66 SS cars. First question he asked me was if I had a California car or not. If the door sheet metal was produced at two or more plants and the two guys setting up the maching to punch the holes for the clips in the door didn't do it the same. Then two different doors as far as the location of the slots.

Well a second set arrived and the clips are in the right place. So indeed there are two different styles. Liked the second set from Repops over the PUI set.

Had the same issue with REPOP fuzzies on my sons' 66 Nova - clips in the wrong place. 90% of the clips fit and had to make some adjustments so the others fit... Possibly 2 different styles there too :(

Could be, the guy at PUI ( Ron Fox) said this is a common problem. One should measure the location of the clips and talk to the vender/ supplier about location.