Yes, problems for 3 reasons :
1) the finbox is Tuttle, not Deep Tuttle, so with 70 cm fin leverage and your heavy weight, you'll risk to ruin your finbox. Max fin is 54 cm for standard Tuttle.
2) width one foot off (30 cm from tail end) is 54 cm. Usually, don't go over that width for your max fin size, you'll gain nothing going too big.
3) for 8-12 knots wind range, I feel the board might be too small for your weight (a 105 kg friend is using the same board with a 9.5 sail and stock fin as of 12 knots). A large iSonic 150/155 or Formula will get you much better for that low wind range IMHO (same friend is using a Formula + 11 m2 sail for that range).