Great question - thanks for trusting me for an answer! Weighted presentations are so speed and line diameter dependent, it makes it difficult for me to give you a really accurate answer so I am going to approach this question a little differently.
I'll preface this also by saying that I rely HEAVILY on Precision Trolling Dive Curves - PRECISION TROLLING | thenextbite.tv
70 feet back on a 300 series Bandit with the line I troll (Berkley 10lb Trilene XT) will put that bait down (regardless of speed) to around 13.5 feet. 65 feet of line is 13' and 75' of line is 14' down. I didn't look at the dive curves for Fireline - but 10 pound test (4 pound diameter
#6 Flicker Shad down 13 feet = 120 feet of line (10 lb XT) (add 2 more feet of depth if using 10/4 fireline)
#5 Flicker Shad down 11 feet = 150 feet of line (10lb XT) (add maybe a foot more with 10/4 fireline)
To "kinda" answer your Q: I would suggest a PSS2 (1/4 ounce split shot) at lengths of 100 to 150 feet of line and if you get bit - duplicate the presentation. Again - speed becomes a factor with weighted presentations, higher speed = more lift - slower speed = more drop
I would highly suggest investing in the precision dive curves - they have both stickers and I-Phone Apps