Hi Grant, I see you have some good information from others in response to your post about rope and block sizes.
As you are no doubt aware there are quite a few historical and interpretive sources with many accompanying tables for a variety of ships. I find I get bogged down trying to find the right table/s for the year, size and type of vessel I am interested in. However, there is a good general guide that may assist you, which is the Appendix of James Lee’s “The Masting and Rigging of English Ship’s of War”.
He firstly draws from contemporary masting tables or from proportionate tables given in contemporary books and manuscripts. The proportionate diameters of the masts then, later in the appendix, helps work out the proportionate rigging sizes. The standing and running rigging are worked out in relation to the appropriate mast stay. Following his pages feels like a flow chart in words but it’s reasonably intuitive. For the block sizes, deadeyes, hearts etc., at the end of the Appendix, he has worked out sizes based on the size of rope reeving through them.
The Appendix does, over seven large pages, provide some good general information that may suit your needs. Trying to fiddlearse around with circumference to diameter, imperial to metric, fractions of inches etc. and a mix of it all is a headache. Lees has obviated, as he says, “the need for masses of tables” and has therefore worked out the sizes, proportionally. I hope this helps or at least gives you another source.