We're looking at 600 years back, so are you saying there's 18000 novas to examine (30 per year) across that period?

Their conclusion in the OP was AIUI that _many_ stars produce novae serially. So we should surely be able to match series of novae (along a stars trajectory).

Do you know are English language details of the historic Korean record available (are they in the paper)?

http://www.cbat.eps.harvard.edu/nova_list.html shows very few recorded novae, is this a listing including the dozens per annum you mention?