Grip shape differences

[pow]

I currently use Wilson racquets and I was wondering how the grips compare if I make the switch, I don't want to buy the wrong size grips.

I'm looking at (Yea I know, I see to be interested in some models nearing extinction):

Please describe the grip differences to Wilson for these racquets and also what grip size I should be looking at if I normally use a 4 3/8 with a tournagrip (thin grip) Thanks a lot.
Prokennex Redondo mid (currently, I'm thinking of 4 1/4 with a Wilson Progrip over it since it's leather and I could afford using a thicker overgrip.)
Yonex RDX 500 mid (maybe just a 4 3/8?)

and the Wilson K6.1 but that's the same shape, I believe.
Thanks for any help!

 

[BLiND]

I've only used Prince, Wilson, Head & Yonex... all very different.

Wilson = Rectangular-Octagonal
Yonex = Round-Octagonal
Head = Rectangular
Prince = Squarer

As for size, I found Prince to be slightly larger, and head slightly smaller.

 

[Michelangelo]

I've only used Prince, Wilson, Head & Yonex... all very different.

Wilson = Rectangular-Octagonal
Yonex = Round-Octagonal
Head = Rectangular
Prince = Squarer

As for size, I found Prince to be slightly larger, and head slightly smaller.

I've only owned Wilson, Prince and HEAD, and also demoed Babolat, Fischer and Yonex. Compared with Wilson, Prince's grip is a bit more square (technically, more equilateral, since there're 8 faces instead of 4), HEAD's toward more rectangular (narrower diagonal faces). Yonex, Fischer and Babolat feels about the same (not quite sure about this since I only demoed them, not owned them).