I strongly recommend sticking to PC standards: start bit is high, data bits
are inverted (1 = low, 0 = high) with one line bit per data bit, data rolls
right on send/receive, stop bit is low.

The technique you refer to (put a 1-0 on the line for a 1 data bit) sounds
a bit like Manchester encoding, used in radio and other media that don't
like long time periods without a voltage/level change.  Serial comms is
usually (always to my knowledge, but someone will find an exception if I
say that) one line signal per data bit:

Byte to send:   0xAA    b'10101010'
Bit location:             '76543210'
Line signals    H       H       L       H       L       H       L       H
L       L
Meaning Start   0       1       2       3       4       5       6       7
Stop

I've attempted to show transmission sequence with the 7654 stuff.  All line
bit signals are the same size, 104us seems good for 9600 bps. Does that
help?