This is my radio config, with your changes in bold. I’ve left the TXpower for you to decide:
[1] S0: FORMAT=27
[1] S1: SERIAL_SPEED=57
[1] S2: AIR_SPEED=64
[1] S3: NETID=8
[1] S4: TXPOWER=?
[1] S5: ECC=0
[1] S6: MAVLINK=0
[1] S7: OPPRESEND=0
[1] S8: MIN_FREQ=915000
[1] S9: MAX_FREQ=928000
[1] S10: NUM_CHANNELS=50
[1] S11: DUTY_CYCLE=10
[1] S12: LBT_RSSI=0
[1] S13: MANCHESTER=0
[1] S14: RTSCTS=0
[1] S15: NODEID=1
[1] S16: NODEDESTINATION=65535
[1] S17: SYNCANY=0
[1] S18: NODECOUNT=2
I picked 64 for air data rate for you to start with based on:
2458bps at 10% = 24580bps at 100% duty cycle
24580bps < 64000bps (leaving some headroom)
These are suggested settings - not tested. Good luck!