You don't filter it when you pour it through the bud, you filter the alcohol AFTER it drips out of the bud, which btw takes a few hours. I actually don't even filter it then, because no debris ever comes out, but if it does then that's the time to filter.
You also do it frozen, or else you'll get crappy green oil. Stuff the bud in the column, not dried, just regular moisture so it's packable without breaking up, and freeze the column, like overnight. Then you just take it out of the freezer long enough to pour frozen alcohol through it then put it back in the freezer to drip out. It's just the final dripping that you leave it sit for a few hours to completely drip out. There's no winterization involved, because the wax never gets dissolved in the first place. It's just like rosin but less crude, because rosin squishes everything out that's meltable, including wax.
A final tip is to use a column with a large enough bottom hole that the alcohol will come right out without piling up in there. If it piles up it will make an inferior product. That's why you don't put a filter in there either, that will definitely make it pile up. I just use a plastic pop bottle with the bottom cut off. The drip hole is the bottle cap with about an 1/8th inch hole drilled in it, not a little pin hole like a coffee thing. I've also done it without the cap at all and it worked fine.