Though normal practice is to install a meter below for liquid line, my problem is that the liquid line is so close to the finished ground level to install a meter. Please suggest alternate options.

 

Do not locate the high and low side taps/ports at the 'top' of the pipe; do not locate them at 12:00.

Instead, locate the taps/ports at 3:00 or 4:00 on the pipe circumference in order to avoid air/gas in the impulse lines.

Probably be a good idea to use a 5 valve manifold so that you can easily vent the impulse lines.