This is a simple guide to the various sync settings for GB/C TASes, concerning the Gambatte core. I may do a version for Sub/GBHawk (alt. GB/C core) and BSNESv115+ (only good SGB/2 core) in the future.
Use official Nintendo BootROM
Sets whether a bootrom (or "BIOS") is used, or whether hacks are used to boot without one. If console verification or BIOS palette switching is desired, then set this to True. Otherwise, setting to True is still highly recommended.
Console Mode
Sets which console is emulated. Set this to GBA if console verification is desired. Set this to GBA or GBC if automatic colorization of GB games and/or BIOS palette switching is desired. Set this to GBA if game specific GBA enhancements are desired. Otherwise, keep this at Auto.
Multicart Compatibility
Uses hacks to detect/support multicarts. Keep this to False for most games. If you are TASing a supported multicart game, set this to True.
Cart Bus Pull-Up Time
Concerns open bus emulation. Keep this at the default 8. Do not change this setting unless you know what you are doing.
Realtime RTC
Ignored for movie recordings.
RTC Divisor Offset
Concerns RTC emulation. Keep this at the default 0. Do not change this setting unless you know what you are doing.
RTC Overflow / Halt / Days / Hours / Minutes / Seconds / Sub-Seconds
Sets the initial internal RTC time and flags. Largely useless, as games generally reset RTC values on bootup if no save file is present. Only useful for save anchored movies.
Latched RTC Overflow / Halt / Days / Hours / Minutes / Seconds
Sets the initial latched RTC time and flags. Largely useless, as games generally reset RTC values on bootup if no save file is present. Only useful for save anchored movies.
Frame Length
Sets the length for an input "frame". In most cases, VBlank Driven Frames should be used. If sub-frame input is desired, then User Defined Frames should be used.
Display BG / OBJ / Window
Sets whether these graphic layers are displayed. Keep these to True.