Are all of the figures (advantages, covariances, and variances) in Appendix B of Kat Walker's Sp 21 book, based on what she described as the 'benchmark' pen of 81.25%? If so, I'd like to know what the advantages at each TC would be (or how to calculate them) for 75-77% pen, which are more commonly found in my area, in order to determine the correct bet sizes. Any help appreciated.