You're carboy will be fine as long as you don't top off too much.
Easy Hefe recipe
Take 4 - 1 gal jugs and place in a freezer for 4-5 hours prior to brewing.
Warm 1.5 gals of water.
Add 1 lb DME. Dissolve.
At boil add 1-1.5 oz hops (3.4-3.8%AA).
Boil 45 mins. Remove from heat.
Add and dissolve 5 lbs DME.
Let sit for 15 mins.
Pour into primary and sparge hops.
Top off to 5.25 gals.
Take temp and hydrometer readings.
Add starter.
You know the rest...
