I'm no expert , but a 1/4 roll would require some top rudder , then when inverted some down elevator , then 3/4 some top rudder again. Now I fly about 12 planes and am not a real great pilot yet , so some of mine roll so fast that I don;t need any other input , and some are slow enough that they require some down elevator. I'm not good enough to work the rudder into a roll yet so my rolls look like "barrel rolls" sometimes. One of my planes can roll slowly perfectly without any other input. A couple of them are so bad like yours that I just don't get them to roll at all (they do have dihedral)

A couple of things that may help is to move the CG back or possibly practice inverted straight flight and then practice knife edge with rudder. I've been practicing knife edge and I hope it helps me with slow rolls to make them perfect. It takes a lot of practice for me at least.