If you choice was as 100% Steem Power for post paying out you will have so profit:

Take $ 100 for estimate
100 x 0,25 = 75 ( that goes back to the curators) so you'll get 100 - 25 = 75$
75$ converted to Steem Power is 75 / 1.247 ~ 60.14 SP

SP 60,14 x $ 5.21 = $ 313.33

If you choice will as 50/50 % you can have:

75/2 = 37.5 / 1 .247 = ~ 30.07 SP (SP 30.07 x 5.21 = $ 159.95)
plus
75/2 = 37.5 x 6.76 = $ 253.5

TOTAL: 159.95 + 253.5 = $ 413.45
$ 413.45 - $ 313.33 = $ 100.12