Pages 6 to 8 of your
scope manual says sight in at any mag, but use 9x for range lines to work. Your Marlin with FTX loads is a legit 250 yard rifle, and only a few inches worse than 150gr/3006 loads those lines are intended for(out to 300). I'd bet a beer if you sight in about 1.5 or 2 inches high at 100 the 200 and 300 lines will within an inch or two.