diff --git a/Control/CalypsoExample/Simulation/scripts/faser_simulate.py b/Control/CalypsoExample/Simulation/scripts/faser_simulate.py
index 1c8320245e6ecfa61857a6d60d04d1cf8d538d54..09c61de889fefd45736504facfdfdf934790a44c 100755
--- a/Control/CalypsoExample/Simulation/scripts/faser_simulate.py
+++ b/Control/CalypsoExample/Simulation/scripts/faser_simulate.py
@@ -148,7 +148,7 @@ if __name__ == '__main__':
 #
     if args.geom == "TI12MC":
         # 2022 TI12 geometry
-        ConfigFlags.GeoModel.FaserVersion = "FASERNU-03"  # Geometry set-up
+        ConfigFlags.GeoModel.FaserVersion = "FASERNU-04"  # Geometry set-up
         ConfigFlags.IOVDb.GlobalTag = "OFLCOND-FASER-03"  # Conditions set-up
         # TI12 detectors
         detectors = ['Veto', 'VetoNu', 'Preshower', 'FaserSCT', 'Ecal', 
@@ -156,7 +156,7 @@ if __name__ == '__main__':
 
     elif args.geom == "TestBeamMC":
         # Define 2021 test beam geometry
-        ConfigFlags.GeoModel.FaserVersion = "FASER-TB00"   # Geometry set-up
+        ConfigFlags.GeoModel.FaserVersion = "FASER-TB01"   # Geometry set-up
         ConfigFlags.IOVDb.GlobalTag = "OFLCOND-FASER-TB00" # Conditions set-up
         # Testbeam detectors (trigger layers are actually veto counters)
         detectors = ['Veto', 'Preshower', 'FaserSCT', 'Ecal']
diff --git a/Generators/ForeseeGenerator/share/generate_forsee_events.py b/Generators/ForeseeGenerator/share/generate_forsee_events.py
index 9190f70fa37fd0094f8320e5e8fa63259c56bd2d..cb8db6c591469f837dd61a83885138b6c9bccbf5 100644
--- a/Generators/ForeseeGenerator/share/generate_forsee_events.py
+++ b/Generators/ForeseeGenerator/share/generate_forsee_events.py
@@ -9,7 +9,7 @@ class ForeseeGenerator(object):
     Generate LLP particles within FASER acceptance from FORESEE
     """
     
-    def __init__(self, modelname, energy, mass, couplings, daughter1_pid, daughter2_pid, outdir = None, path = '.', randomSeed = 12345, t0 = 0, notime = False, suffix = ""):
+    def __init__(self, modelname, energy, mass, couplings, daughter1_pid, daughter2_pid, outdir = None, path = '.', randomSeed = 12345, t0Shift = 0, zFront = -1.5, notime = False, suffix = ""):
 
         self.modelname = modelname
         self.energy = energy
@@ -21,7 +21,8 @@ class ForeseeGenerator(object):
         self.path = path
         self.version = 3  # Forsee "version"
         self.seed = randomSeed
-        self.t0 = t0
+        self.zfront = zFront
+        self.t0 = t0Shift + zFront
         self.notime = notime
         self.suffix = f"_{suffix}" if suffix else ""
         self.nbinsample = 1
@@ -447,7 +448,7 @@ class ForeseeGenerator(object):
 
         filename =  f"{self.outdir}/events_{self.energy}TeV_m{self.mass}GeV_c{self.couplings[0]:.1e}to_{self.daughter1_pid}_{self.daughter2_pid}{self.suffix}.hepmc"
 
-        _, weights, _ = self.foresee.write_events(self.mass, self.couplings[0], self.energy, filename, nevents, zfront = -1.5, seed = self.seed, decaychannels = [self.mode],
+        _, weights, _ = self.foresee.write_events(self.mass, self.couplings[0], self.energy, filename, nevents, zfront = self.zfront, seed = self.seed, decaychannels = [self.mode],
                                   notime = self.notime, t0 = self.t0, nsample = self.nbinsample, return_data = True)
 
         cfgname = f"{self.foresee.dirpath}/Models/{self.modelname}/" + filename.replace(".hepmc", ".cfg")
@@ -538,7 +539,7 @@ def production(args):
         for m in masses:
             print(f">>> {nrun}: {data['model']} ({m} GeV) -> {data['pid1']} + {data['pid2']} with couplings = {couplings[0]:.2e} @ Ecom = {args.Ecom} TeV") 
 
-            f = ForeseeGenerator(data["model"], args.Ecom, m, couplings, data["pid1"], data["pid2"], path = args.path, randomSeed = args.randomSeed, t0 = args.t0, notime = args.notime, suffix = data["name"])
+            f = ForeseeGenerator(data["model"], args.Ecom, m, couplings, data["pid1"], data["pid2"], path = args.path, randomSeed = args.randomSeed, t0Shift = args.t0, zFront = args.zfront, notime = args.notime, suffix = data["name"])
 
             with open("events.txt", "a") as fout:
                 f.events(40, fout)
@@ -591,6 +592,7 @@ if __name__ == "__main__":
     parser.add_argument("--nevents", "-n", default = 10, type = int, help = "Number of HepMC events ")
     parser.add_argument("--randomSeed", "-s", default = 1234, type = int, help = "Random seed for HepMC generation")
     parser.add_argument("--t0", "-t", default = 0, type = int, help = "Time offset for start of decay volume")
+    parser.add_argument("--zfront", "-z", default = -1.5, help = "Minimum FASER z coordinate for decays (in meters)")
     parser.add_argument("--notime", action = "store_true", help = "Set all vertex times to 0 rather than calculating from start of decay volume")
     parser.add_argument("--suffix", default = "", help = "Filename suffix")
     args = parser.parse_args()
@@ -614,7 +616,7 @@ if __name__ == "__main__":
         print(f"   decay = {args.pid1} {args.pid2}")
         print(f"   couplings = {couplings}")    
         
-        f = ForeseeGenerator(args.model, args.Ecom, args.mass, couplings, args.pid1, args.pid2, outdir = args.outdir, path = args.path, randomSeed = args.randomSeed, t0 = args.t0, notime = args.notime, suffix = args.suffix)
+        f = ForeseeGenerator(args.model, args.Ecom, args.mass, couplings, args.pid1, args.pid2, outdir = args.outdir, path = args.path, randomSeed = args.randomSeed, t0Shift = args.t0, zFront = args.zfront, notime = args.notime, suffix = args.suffix)
         
         if args.hepmc:
             f.write_hepmc(args.nevents)