Just avoid putting side forces on the gauge hose interface. It will flood at any depth. I placed some silicone adhesive around the hose where it enters the gauge. (That was before I made my own.) Your use of the gauge is appropriate for the diving you do at this time.
I have some pics of a defective unit at
http://www.airheadsscuba.com/po2gauge.html if you are interested. It shows where to expect problems.