You can use the 10lb to fill the 1lb! What i do/did was stick the 1lb bottle in a ice chest(try to get it as cold as possible) warm the 10lb bottle to about 1000-1100PSI, use a "STEEL BRAIDED N2O LINE" between the bottles, open the 1lb bottle up all the way, then same thing with 10lb bottle. You will hear it "filling" ounce the sound goes away, i usually SHAKE THE PISS OUT OF THE 1lb bottle, at the same time turning upside down & back right side up(your trying to get as much AIR OUT AS POSSIBLE)you can also weigh it, but it usually wont go over seeings how your not using a PUMP to force it in. Then close both bottles, "CRACK LINE & LET IT BLEED OFF" and your done. Hope this helps