If I go to store ->Cigar Tobacco->chavetas I am presented with a selection of 5 chavetas. 3 are described as " American style" and are blue in color (#1, #2, #3b). The other 2 are natural or stainless steel in color (#4B and #5). The difference in price is not significantHow would one go about selecting the correct knife? Here are the similarities and differences as I can deduce from reading the descriptions:#1 American style, blue, shape 1 (rounded ends) .065 spring steel R45#2 American style, blue, shape 1 (rounded ends) .035 spring steel R45#3B American style, blue, shape 2, (sharp ends) .035 spring steel R45#4B Stainless steel color, shape 2, (sharp ends) .035 stainless steel R45#5 Stainless steel color shape 1 (rounded ends) .035 stainless steel R451. Am I correct that the knives that the spring steel knives are subject to rusting and therefore have a painted finish applied?2. Am I correct in assuming that .035 is adequate for all rolling situations, since 4 of the 5 are fabricated from that thickness. Under what circumstances would a roller select the thicker metal?It seems to me that the sharp cornered tool would be better for fine cutting work like cutting flags and trimming heads. Under what circumstances would the rounded end tool perform better?