Your idea of 'Fun' and mine are somewhat different here. :lol: That's a very painstaking job! It would have to be an otherwise excellent picture for me to even contemplate that much work!
It's an excellent job by any standards - there's very little evidence which I can see of the work done, which is the acid test. Still.... it's very do-able as you've demonstrated very well.
I really don't see that being a 90 minute job though, unless Big G has personally laid a finger on your brow.
