I recently started with a second class and would like to know what is the faster way of gearing second class. Atm I've been using grfit keys and gotten some blood shards on my WD but I'm curious if it's maybe a bit faster to go regular rifts and upgrade rares or if just leeching on barb on t6 is better (although lame)?
Gamble for armor pieces, cube weapons/amulet. Rings are a tough one because both gambling and cubing can take forever and is expensive.
Leeching takes forever and is lame and only makes sense if you want to do a full class switch and need every single item (e.g., you want all 4 class sets of WD to do the conquest).
To just gear up a WD for group rifts, play on any class that can clear GRs fast and gamble using the blood shards. Best is a wizard since you can get rings/amulet on a wiz as well (except for Ring of Emptiness which you can cube), so the only difficult thing to cube is a Sacred Harvester+the staff and all other pieces can easily be gambled. The items are all common except for the belt, so start gambling that. Note that helmet and chest are way more expensive than other set pieces (shoulders being the cheapest), so it might be worth it to just gamble for 6 shoulder pieces and then use the convert recipe in cube to get all 6 different pieces.
Of course the fastest way is to just group up with 3 WDs and ask them to drop pieces they don't need. Once you have someone who will share their loot with you on T13 gearing up an alt is by far the fastest; it took me 2 hours to switch to wizard this season because I had friends who just powerleveled my wizard to 70 in one T6 cow level, then we did some T13 (me on my monk) and an hour later I had enough set pieces to re-roll everything to have the build ready.