Gas Tank Drain

[MGG]

I have a 1934 truck which I do not drive very often. It has the original gas tank with multiple baffles. I would like to occasionally drain out the old gas and put in new. Does anyone have a recommendation/procedure for where or if I could install a drain valve? I do not want to siphon or disconnect the line from the valve at the tank for fear of eventually creating a leak there. Siphoning does not work very well because of the baffles. Thanks