hoosier:I am using a SPG and 6inch hose for 70ft deco bottle. You are right. It isn't fun to see the button gauge at 70ft, specially in low light and visibility. But, I am thinking, 20ft enviornment won't be bad to read the button gauge unless you have an old eye, except the night dive.
We talked about button gauges vs. hose gauges in class and my instructor made a case for the hose gauge because at 70 feet you can use your EAN50 deco stage as a bailout. If you had to resort to using it as a bailout, you would be in a better position to monitor your air consumption. You've already got a reg strapped to the deco bottle. The guage is not going to be more cumbersome.