Hey Brendan! No problem:
• 0xf0 is always the first byte of a SysEx message. It means "Here comes some SysEx".
• 0x43 is Yamaha's manufacturer ID number.
• 0x1n is the basic MIDI receive channel for your device what you want to SysEx, innit. I'm assuming you can count in hex... for MIDI ch. 1, use 0x10. For MIDI ch. 16, use 0x1f.
• After that there is a number that specifies the parameter group. (On my TX81Z a single patch has its editable parameters lumped into two categories. This just tells the TX what category it's about to mess with.) I'm not sure if any of Yamaha's other FM synths work this way, but the relevant manuals should provide some illumination.
• Next up is the parameter number itself (see your TX/DX manual for this).
• Then comes the parameter value.
• Finally, 0xf7 means "End of SysEx".
I highly recommend fucking up your Yamaha with SysEx. Pattr interpolation is asking a bit much - my TX chokes on all the MIDI data, but I've had some success by restricting the interpolation to envelopes, operator volumes, and lfo depth/speed. Some smooth morphing is possible, with care, but I find it infinitely more pleasing to just blast it with horrible quantised stepped data... crusty FM zipper noise madness!
HTH!