Tight is a good thing, Jode. Don't fight tight. You do want a firm roll. What you want is tight with a loose draw. You got halfway there, so don't back up.
It's not tightness that plugs the draw. You've no doubt his on any number of store bought gars that are firm as the devil and yet air can go thru. It could be that you let your filler twist as it got bound. It has that tendency to twist, & you have to fight it. Think of that twist crimping the leaves together. Or, it could be that your filler was damp. Think of the damp gluing the leaves shut together. It needs to be dry enough to crackle just a bit.
Again: It's not tightness that plugs the draw. It's no way for air to get thru that's the problem. So solve the problem -- make a way for air to get thru. Keep it firm but add air. Try this on the next one: loosely roll each filler leaf before you add them to the bunch. In essence, think of making a fistful of soda straws. You can still have the outmost filler leaf flat, to wrap round the others & hold them in place for the binder. You'll see a lot of talk about this method here. It's called "entubado". You don't have to roll each filler down small... just loose, but enough to give you that many air passages. So lay down a nice big rectangle of a filler leaf on your palm, then take the next leaf and roll it lengthwise just a couple three four turns, lay that in your palm inside that leaf rectangle, then the next segment, and so forth, until you have a fistful. Roll them all up together in your binder. That first rectangle holds them together while you bind them up. It still feels tight; but you have created a round bundle of air passages.
Easy street.
Fellers, who knows a good vid showing entubado that they could hand our brother Jody here a link to?