Best upgrades for bows

I dont have the math for the Defense Vs Fortitude grip, but if you think about it, the fortidue may give you a little more health, but the Defense technicaly also increases your health as it lets you better defend the HP you alread have, (unless your fighting a smiter or something that ignores armor, in which case the fortitude would be better). Its really a case of how much damage that +5 armor will reduce.

And as for bow upgrades, the only one iv ever found to be really usefull is the Zealous, iv used one since Beacons pearch and I think the only time iv run out of energy since then is when fighting those pesk mesmers. (Iv also got really high expertise and commonly use barrage, but I dont use any rate of fire increasing skills.)