anyone know of a way to hold pressure as you near the end of the tank.... way to rt the hoses or a check valve? any ider??

If your system (tank, fuel/exhaust lines, carb and engine ) is sealed tight, you should have the correct pressure in the tank, even if it is near empty.
What makes you think your pressure is low?

As far as routing hoses: I know racers like to run extra Loops of fuel line. This gives them a bit more run time and guards against fuel starvation when cornering real Hard.

an engine will run lean as the tank gets empty, if its tuned correctly your ok, if its running hot twards the end of a tank of fuel, you need to richen the hsn a little, like an 1/8. see if that helps.

ive noticed as soon as i am out of gas i open up the tank to refuel sometimes there is exhaust smoke in the tank. is that a sign of a good seal?

thats good, its gonna have smoke in it from the exhaust gasses from the engine.

I didnt know that! Thanks Eddie, I learn a new thing and that makes it a Good Day!
Now that I THINK about it , it makes sense.
Yeah...Ive noticed smoke in my tank to. Wondered what it was from....