Getting a pressure gauge to face the correct way

I am installing a whole house water filter system and I am going to add 2 pressure gauges, one on the input and the other on the output side.
The supply pipe is 1" copper and I have 2 - 1" x 1" x 1/2" tees to which I will sweat a 1/2" x 1/4" C x FIP Copper Female NPT Adapter to accommodate the 1/4" gauge.

What is the trick to orientating the adapter before sweating to ensure that when I screw the gauge in that it is facing the correct direction when tightened. (I don't want to sweat the adaptor with the gauge screwed in)

Alan

My first thought is to screw the gauges into the adaptors and mark them with a file or such then remove gauges and orientate the adaptors and solder them in. Then reinstall gauges.

Why are you installing two gauges? Do you expect there to be a difference?

I would expect the static pressure and flow rate to be the same on both sides.

The static(no flow) pressure would be the same as you say, however, when flowing it would show pressure differential (pressure loss). Some people may like to see pressure differential as filter gets used.
Very common in larger, industrial and commercial applications to monitor pressure drop through items like this, to the point of automating for an alarm or even shut down, depending on the application.
I would do the same if I had a whole house water filter system or even on a PRV.