Slip indicator

[NC3403K]

I started flying my J3 in September. It does not have a slip indicator. I've never flown without one and thought I'd really miss it. To my surprise I haven't. I don't know if that's a good thing or not. I've decided to put one in. I'd like to mount it to the surface of the panel rather than cut a hole. I've seen the 5.5" and 2.5" ones at Aircraft Spruce. The 5.5" strikes me as kinda large. The 2.5" appeals to me more but is twice the price.
I need help!
Thanks!
JLK

 

[JimC]

 

[huston marlowe]

 

[JimC]

 

[lycominglou]

 

[Original 1]

 

[JimC]

 

[NE Cub]

 

[JimC]

 

[Original 1]