I purchased some Rust-oleum Crackle Base to see what, if any, other patterns I could make other than the standard grid style. (I have not used the Crackle Top coat on these test pieces)
Following the instructions (to the letter) of brushed straight lines for the first emulsion coat followed by brushed Crackle Base following the first emulsion coat lines and then the second, 10% thinned, emulsion coat at right angles to the first and I got this standard grid pattern. The larger cracks are where the emulsion coat is thicker.
Trying to alter the pattern I tried crisscrossing the brush strokes. Where the top emulsion coat is thin the cracks have followed the brush strokes but where it is thicker the cracks are more random.
Another attempt; but this time by revolving the brush whilst moving it in straight lines. Where the emulsion is thin the cracks appear to have followed a curved track but where the emulsion is thicker the cracks are again more random.
The last attempt was with a roller and this has just made random cracks; where the emulsion is thin the effect appears more like crazing than cracking. The un-cracked area at the top is because the second emulsion coat is too thick here. The instruction say not to work the paint, just lay it on, as this can mix the Crackle Base and the emulsion.
I quite liked the rollered finish running across just up from the bottom and tried to reproduce this again but with no luck, just a crazed effect; I think I over thinned the second emulsion coat. I think the viscosity of the emulsion and the thickness of the coating are crucial to the repeatable success with this finish.
The instructions say that practice is required to get a repeatable effect; a great deal of practice if you are trying to get away from the standard grid pattern, me thinks.