I used Jarids for a long time now switched to heavy axes. I didn't like Javelins I found them a bit too weak, I find they didn't have the stopping power of jarids and even with pierce damage, heavier players just laughed off Javelins.
Heavy axes don't hit tincans as quite as hard as jarid (still hard enough), but hurt everyone else pretty bad, and unarmoured horses too. They have a few other advantages over jarids, they have a much faster wind-up speed, which is important tactically cuz sometimes you have really have a good chance to get a shot in, but not much time. Also they are a bit more accurate. Not much more but it was pretty noticable and nice when I switched to them. Axes are also much easier to retrieve off the ground, they really stand out while Jarids and Javs get lost easily, which is a small +.
I spent a long time using just 1 stack and a big 2 slot shield. Recently switched to 2 stacks and a 1 slot shield. I bought a set of +3 axes and wanted to get more use out of them, and found a 7.5 weight shield to be enough. I really like the extra axes (sweet sweet +3 ones), and get about half my kills now on battle with them, bring down a lot of horses too. if you're just starting as a thrower tho you can just stick with one, saves you a bit of money, and it will teach you to use them better & more carefully if you have a more limited supply.