Are there any gauges that work well for tires using Presta valves? Is it practical to try to check pressure levels in high pressure/low volume tires used on most road bikes?

I just finished up a new bike that I took out for it's first real ride today today. I built this up just for use on a couple of "rails to trails" MUP and a couple of rides I do that are a mix of gravel and paved roads. I inflated the 700C x 37 tires to 50 psi front and 60 psi rear to start, the tire's specs call for a max pressure of 70 psi. I wasn't long into the ride before I realized that the tires were way too hard but I didn't want to just let air out because I had no way of determining what pressure I was running. As of right now the only way I can determine tire pressure is by inflating TO a pressure. My mini pump that I carry with me doesn't have a pressure gauge.

The only pressure gauges I've used are for Schrader valves are just push on, they always lose a little air going on and off but considering the volume it's insignificant. I don't think same system would be suitable for use in many of the tires that use Presta valves. I looked at a suspension pump once that screwed on the valve and sealed before opening the valve with a separate level. That system would only allow the volume of air required to fill the gauges chamber. Is there something like that for Presta valves?