Thank you, Bernard, for the link to this topic from the related Angus & Greener topic.
As to measurements, In future, I shall defer to your preferences and try and include measurements of British and Irish glass in Imperial units (though I shall also continue to include metric measurements for those sufficiently removed geographically or chronologically from the Imperial system to find it a mystery).
I can see that a glass mould would need to be made within reasonably tight tolerances, but the final glass items that comes from it must surely vary in size within much wider tolerances – is there any real merit in inappropriate precision in measurement (as in the cases of estate or land agents who quote their land areas to the fifth decimal place of an acre or hectare and then conclude with the caveat “or thereabouts”)?
For pressed glass pieces, I assume that dimensions to the nearest millimetre will suffice – I’m not sure where my metric callipers and micrometers are at the moment. (In the case of the Angus & Greener plate, I think 165mm is only about 0.1mm away from 6½ inches). As to the Imperial measurements, would you like them to be in fractions of an inch (and if so, how small a fraction), thousandths of an inch for those who need true Imperial engineering precision, or will decimals of an inch to 2 significant decimal points do?
In respect of the most appropriate section for posting new topics so that
... new topics are seen by as many as possible
I could understand initially putting (or keeping) a new topic in the general Glass section if it referred to a general point or was seeking identification or attribution, but there is absolutely no question as the country of manufacturer, attribution, detailed identification or dating of the Angus & Greener RD 117501 pieces. Am I to imply that all my new topics should be initially posted under the general Glass section, thereby seeking the widest possible exposure on GMB, and only moved to a specialist section when deemed appropriate by the moderators?