In the presence of specialist publications I view Spink's and Chris's book predominantly as a price guide! Which means, at least for me, that popularly collected varieties, especially higher value/rarer and significant 'types' would do well to be included! I accept that a 1599 Anchor Sixpence of E1 will not be separated out far beyond an issue type, on account there are not a large number of collectors collating E1 date runs, but I can see how the 19th & 20th C bronze collectors (as an example) would benefit!