It'll be time consuming if they follow the same route. Grade 6 nodes 6k cuts each 3 main regions 18k cuts, 144 cuts an hour maybe, 125.5hrs, nearly 5 days of just cutting lol. Which is just a tad shorter then the objective to get all the work done from 1-5 in all 3 regions, 21960, 152.5 hrs, 6.3 days worth of cuts lol. Maybe it'll be quicker with changes made to DOL/DOH but it'll definitely be a tedious task to get the upgrade lol.

DOH synths might be 6k for 51-60 or 51-55 based on how high lv cap is increased. If it's just 51-55 then perhaps it will be 4.5k synths if it's 51-60 then 6k synths. 4..5k synths would be about 70 hasty hand synths an hour 64 hrs, 2.6 days and 6k would be 85.7hrs 3.5 days, while it might look shorter DOH requires gil input as well as the mats needed for 4.5/6k since which would basically be 45.5 stacks of logs or 60.6 stacks of logs lol which is a lot. If they were maybe 2.5k each that would equate to 11.25/15mil gil worth of logs, and that's the cheapest route other crafts might not be as lucky.

Of course with changes to DOL/DOH the objectives may change completely but as it stands now the above is most likely the task that would be required to obtain the upgraded luminary if they do indeed make them upgradeable.