π I'm afraid you have to try them all... but, seriously, you have many variations of the same film depending of the sensitivity, so start trying the first one of each group because the others have quite similar effects on your image with the exception of the exposure of course. Also you could try this free program called "Motiva real camera", which has the previews of the CRF. The developers cooperate with Giannis and the Thea team. π