We are designing gRNAs for targeting essential genes in human cells, and finding that common online tools give very inconsistent scores for same gRNA sequences (e.g. a gRNA scored at 26/100 by one tool is scored at 76/100 by another). Given how popular CRISPR is, has anyone validated gRNA scores by different programs and follow-ups of CRISPR outcomes (integration, mutation, etc)? Or has anyone systematically CRISPRed the same locus using gRNAs of a wide range of scores, and compared the outcomes? I remember in the age of microarrays there was this publication, so I am looking for something of a similar sort:

https://www.ncbi.nlm.nih.gov/pubmed/12454646

Thank you all in advance!