Mhhh, the difference in weight seems less than I expected.
I build an old one and that weighted with scale cockpit and 2 heavy pilots (cockpit and pilots weighted around 800 gram) and full fuel +/- 17,5 kg.
That one was powered with a P120RX (13,5 kg thrust) and flew nice.
Placed everything as far forward as possible, LiPo`s in the nose and still needed 200 grams of lead.
But yours will fly great, I`m sure.
Have fun with it.
Grt,
Berto.