I have a very similar set-up for my bow as you mentioned, 70lb at 28 in draw. For my safari, I used Carbon Express Maxima Blues Streak arrows (350 Spine, 8.3 gr/in), 3 3" plastic vanes, bull dog nock collars (4.6 grains), carbon express nocks (10 grains), 100 grain Muzzy fixed broadheads. I know this my be a little light for most, but I prefer speed and accuracy over weight, that is my personal preference. I took a blesbuck, impala and Kudu without any issues. I have also taken Caribou and White Tails with this set up. I have taken my set up Moose hungting, but Bull Winkle has not given me the opportunity to shoot him....yet. I also have some Full Metal Jackets, just have not put the time into fully trying them out yet becasue my current set-up works for me at this time. As for the mechanical vs. broadhead issue....I think Norwegianwoods said it, - Sadly many that chooses to use mechs do so because they don't manage to tune their bow to shoot well with fixed broadheads - In recent years mechanicals have benifited from better technology, I am just not ready to switch to them yet....again a personal preference.