Hi, Samson,
Yes, you are correct in interpreting the line that sets the Chorus effect you want.
There are 2 SysEx messages related to the Insertion Effect (Effect #1), that you should delete:
001:2:0000 Sysex=F0 43 10 4C 02 01 40 06 00 F7 DSP1 Type Delay Left Right
001:2:0000 Sysex=F0 43 10 4C 02 01 5A 01 F7 DSP1 Connection = System
If you want, you can also delete the following messages, which set the rest of the DSPs to different effects (and turn them off), unless you want to keep them:
001:2:0000 Sysex=F0 43 10 4C 03 02 00 05 10 F7 = Delay Left Center Right1
001:2:0000 Sysex=F0 43 10 4C 03 01 00 05 10 F7 = Delay Left Center Right1
001:2:0000 Sysex=F0 43 10 4C 03 00 00 61 22 F7 = Unknown type for Instrument : None
001:2:0000 Sysex=F0 43 10 4C 03 00 0C 7F F7 is set to Off
001:2:0000 Sysex=F0 43 10 4C 03 00 0A 6E F7 Parameter 9 = 6E
001:2:0000 Sysex=F0 43 10 4C 03 03 00 57 10 F7 = Unknown type for Instrument : None
001:2:0000 Sysex=F0 43 10 4C 03 03 0C 7F F7 is set to Off
001:2:0000 Sysex=F0 43 10 4C 03 03 0B 24 F7 Parameter 10 = 24
001:2:0000 Sysex=F0 43 10 4C 03 00 0B 00 F7 Parameter 10 = 00
For more information, you can find (most) of the settings that can be altered via SysEx messages in the Data List manual, which can be found on Yamaha's web site. Looking at the "PSR-SX900/PSR-SX700 Data List", the parameters for changing Reverb, Chorus and DSPs can be found on pages 103-105, and the actual SysEx message on page 117.
To clarify a little: the SysEx message is "XG Parameter Change" (found on p.117). Most of the settings of the keyboard are controlled by setting XG parameters using this message. The tables starting at page 103 contain the documented parameters that you can change, indicating for each parameter the address (3 bytes) and the data (number of bytes depends on the parameter) that should be sent. In XG parlance, EFFECT1 includes Reverb, Chorus and so-called variation, which is DSP1 (these are "global" effects, which are set for the whole keyboard), whereas EFFECT2 is the DSPs that can be assigned to each channel as insertion effects (DSP2 - DSP9+ depending on the model of the keyboard).
When setting the DSPs, the Hex code for each effect can be found on the tables starting at page 48, and the parameters for each effect spread across two tables starting in pages 61 and 74 respectively.
Once you get the hang of it, its not that complicated, but the information is spread out all over the place!
Regards!