Not sure if its called darce or garce lol 
No. Same grip but on opposite sides. Anaconda locks up on the back/lat while D'arce locks up on the neck side. 
Doesn't one also have a variation with the gi?
both arm triangles
darce, my right arm goes under your left arm and then under your chin
anaconda, my right arm goes under your chin and then under your right arm
DSCH - Doesn't one also have a variation with the gi?
can do both. most popular is probably the darce with the gi called brabo by most
some argue about this shit, but i play a heavy darce/brabo game and refer to gi version (actually using gi tail of opponent) as brabo and no gi as darce (note: darce choke can happen in the gi, you just dont use the gi to anchor your hand)
this is prob confusing if you dont train, just youtube that shit