I used to take the filter out and let it fill up however when done I would remove the filter casing and dump the antifreeze down the drains. If you go the empty bottle route put it in upside down so the cap cannot get wedged into the fittings. Does not happen on all but some filters are about that size at the top.
Now I removed the filter and use an inline one...so much easier.
remove the filter and just fill up the canister. what is its capacity, maybe a quart? at $3/gal for antifreeze that is only $.75 to fill the canister. i've seen bypass plates for around $10 that will let you save that $.75. what's that, a 13 year payback?
2015 cardinal model 3825fl
2015 dodge ram 3500 dually