Well that's as good as it gets as far as data go, because I don't know of any similiar German range table for the G or K series. However datasheets give almost exactly the same max. ranges for G and F as about 600/1000
miles w. or w/o a droptank. Some British G datasheet give as high as 1200 miles.
As a matter of fact, the mid-1942 on the Zeugmeister notes the F-4's range as 1600 km, and the early G-series as 'vorausichtig(sp?) besser' (foreseen to be better).
Re: DB 605A vs 601E the former was an improved version of the latter, and the 605A had better fuel effiency (greater CR and other improvements). For example the 605A at max. cruise seem to develop about 50 HP more with the same amount of fuel used. You are of course right about the increased drag of the airframe, I guess the better engine just evened that out.
Other than, feel free to play with any condition, combination and power setting you deem realistic, that's why I gave the link to the table.
BTW it would also be interesting to know how long Lightning could last over an enemy airbase and still return, preferably while disengaging at high speed.