According to the table the fronts are 189% stiffer than stock and the rear 55% stiffer+helpers so however you look at it the front is MUCH stiffer.
Are you comfortable with the front stiffness? Then stiffen up the rear and vice versa.
I see 3 solutions to get a decently balanced car to work with(camber,tires,alignment etc)
1. Keep 24 bars and add 33 rear+helpers (last example in the table) (About 190% stiffer all round against stock/ If your helpers add around 30%?)
2. Keep 24 bars and 29 rear and add 135% trough heavy helpers to get same balance as above (will strain the shocktowers but may be ok, safer to reinforce)
3. Add 21-22 front bar and run 29+helpers (This will give a car thats about 70-100% stiffer than stock)
Or you run as is and have a super stable highway missile..