Hi, sorry for the delay in getting back to you.
I have done some looking around, and the following information is based on what's available on the PokerStars website as shown here.
| Stakes |
2 players: % / cap |
3-4 players: % / cap |
5-6 players: % / cap |
| $0.50/$1 |
4.5% / $0.40 |
4.5% / $0.40 |
4.5% / $0.40 |
| $1/$2 |
2.0% / $0.50 |
3.0% / $0.80 |
4.0% / $1.00 |
| $2/$4 |
2.0% / $0.50 |
3.0% / $0.80 |
3.0% / $2.00 |
While I am not sure about whether the difference between $0.50/$1 compared to $2/$4 will be as much as 30% on average as I have little to no personal experience with average potsizes for fixed limit on these levels, but as you can see the rake is lower in percentages, but the cap is higher for all amounts of players at the table.
Hopefully this is helpful for a graphical overview.
Regards,
Richard