I would definitely go looking for one with at least 5 FULL spirals, maybe more. You don't want to get stuck with one of these puny specimens in your picture... look at that! TWO spirals?! They should look like blown out blackbuck horns!!! And look at how small they are! Impala should weigh at least as much as a small rhino! Common judgement of trophy quality rule of thumb is: the one you're looking at is a trophy when the poor beast cant get its head up above it's shoulders because the 8 foot horns drag on the ground. Or it's neck looks like a body builder from holding those 40 pound helixes.
P.S. This is my professional-keyboardwarrior-expertonallthingsontheinternet- opinion and should not be disregarded as simpleton shenanigans.