It wasn't as easy as sparkedit since that has a visual interface, but I prefer to use my own program. Plus it means no emulating or bootcamping.
Eschaton 0.4.1:
Turrets:
Load a map, select vehi: mp_warthog
In the reflexive editor window selected the main reflexive
Selected enum 32
Selected the kill physics option and pressed the pick flag button
Selected the lower turret to floor option and pressed the pick flag button
Selected the kill antenna option and pressed the pick flag button
Go up and select the seat reflexive
The first one is w-driver so selected string32: name and changed it to P-drvier
The second one is w-passenger so selected string32: name and changed it to P-passenger
In the main window select the mod2: mp_warthog
Apple-D open the dependency swapper
Replaced all the dependencies except for the three chaingun shaders with ligh teleporter coop to make it invisible.
Closed d-swapper (next tag would slow down the program if it searched for dependencies)
Select the scnr tag.
Press the edit button that appears on the bottom of the main window to open the scnr edit window.
Because it's rebuilt, the names were scrambled but since the spawn points weren't changed, used a cropped screen shot of what the list should like, a reference map of bloodgulch (included in download) and some guess and check to move the spawn locations of the warthogs where they should be as turrets.
Hexed the teleporters since they were new things and had to use empty chunks. Hexed the flag since the scnr tag has a weird organization for itmc tags and wasn't been integrated into Eschaton yet.
Eschaton topic on halomods (0.4.1 is demo compatible, 0.4 isn't.)
Direct download of 0.4.1 for those who aren't registered