Bacterias response to antiseptics experiments

[sld94]

Hello I have the following bacteria sources available to me
E. coli, broth
S. albus, broth
S. marcescens, broth
P. fluorescecs, slope
B. subtilis, broth
I was thinking of setting up agar plate with a different antiseptic in each quadrant and test which produced the largest zones of inhabitation. But I need to make this experiment slightly more complex as I am in year 12. I was thinking along the lines of investigating which type of antiseptic (Alcohol base, Iodine base, Peroxide base and water) would work best against gram pos and gram neg respectively and if the shape of the individual bacteria had an influence in its resistance to the antiseptics.

If anyone has any ideas on this or any suggestions please comment and I would appreciate any feedback.