My team is pretty much set in stone and I had this idea...
Two of us, would throw majority of our gold to the blacksmith and the jeweler in order to level them up as fast as possible. One would work on blacksmith only and another work on jeweler only. So instead of trying to get them both up at the same time which would take a lot longer and a lot more gold we split them up. Then whenever someone wants some weapons or armor made etc... you just give the person who leveled up the blacksmith the required gold and resources, item gets made and then given to you. Same thing for the jeweler.
I figured this would be good to do at first because it would save gold while still being able to get the goods but of course eventually later on everyone will level both of their own up.
Personally the jeweler isn't going to help a lot at all until way later in the game. Being able to craft gear = to the content your playing is a lot more valuable. I would choose one person and dump all your gold on them to level the blacksmith as fast as possible, THAT will be the fastest way =D Unless I'm way off I don't see a reason to level the jeweler early on at all if your goal is to level the quickest.
1 st of all after lvl 4 you need training tomes to lvl him up, so your friends would have to give them to you when they find them so you can can lvl it fast===> they won`t have them when they will need to lvl up their artisans.
2 nd the really good stuff comes in induvidual recipes, so your friends have to give them to you so you can forge them===>those rare recipes will become bound to your artisan, and for example if i find a really good recipe, i want to have it on my artisan rather than a friends because, things may get sticky..