Hi again,
Pete, I made the test and here are the results:
RMC give Heading, position, speed but no altitude
RMA nothing
GPRMZ Heading, position, speed but no altitude
RMC+GPRMZ Heading, position, speed but no altitude
GLL nothing
GGA Altitute and position but no heading or speed
AV400 nothing
So, the best setting for Sentence is using RMC+GGA
About the speed I tested a wide range, and the best value is 4800bps. It also worked with 9600 but I was a little bit inestable, I mean, sometimes works and sometimes not, but with 4800bps works fine. Above 9600bps it doesn't work.
I hope this information will be usefull for you and for others.
Best regards,
Alejandro