Aggregates form over time. The less time between reconstitution and use the better. Or the less time between filtering and use is better.
Since you're using a vial every 3 days, I'd reconstitute however many vials would fit into a 10ml syringe. Draw them all into the syringe, remove needle and attach filter, reattach needle.
Then backfill an insulin syringe just before you use it. Once you do it a few times it only takes seconds. Then whatever aggregates grow in syringe are filtered out and there's not enough time for new ones to form in the insulin syringe,
If that's too much work, just filter a few vials at a time (draw into syringe, attach filter, inject back into vial) and use however you normally would, or backfill a bunch of insulin syringes in advance from the filtered syringe,