Awesome news! I'm glad to hear your efforts with the hex editor are working out.
I'm assuming any file you make will then have to be uploaded into the game as usual, so all the stats will still get dropped by Madden? In that case, I'd recommend upping the speed for all players somewhat. As many have mentioned, the game tends to drop speed anywhere from 5-15 points, so very few RB's, WR's, and CB's end up with speed in the 90's.
If you bumped the fastest of them up to 95-99 in the file, when Madden converts it over some will still be in the low to mid 90's.
The other item that's odd is that it seems sometimes the players dont have any toughness. Be sure to make sure that exports over in the file.