Its always better to use wheel filters, and I also, even though I am an experienced IV drug user of many years, still have never once even seen a wheel filter or used one.. no one I have ever used IV with in the past, has used them either... most have no idea what the fuck it is! I ask them "have you ever tried using a micron filter instead of a cotton before?" and they look at me like I'm crazy, like "wtf is that?".
If I had easy access I would use them, but I don't, and I have been using cottons, tightly rolled and wetted first so they are able to be more compact, thus helping filter the solution better.. I mainly shoot subutex, but used to shoot D's and dope a lot! ALOT ALOT! and oxy, and opana, and etc.... I used to IV any good water soluble opioid there was available to me.. D's were one of my favorites, and they were the easiest of all the pills I mentioned to filter, truly! I would use at the very most, 2 cottons, and filter them 2x through those 2 cottons, usually all I needed was 1... and I would get a crystal clear solution, like I didn't even have dilaudid in it, just straight water like looking... clear as can be, from what I could see.. now its not GOOD for you to filter thru cottons, but it does work, and is a lot easier for someone, who is a rookie at using IV and has no one, in person, to show you step by step how to properly use a micron filter... Be safe, and if you have access to micron filters, practice a couple times, just using something your not actually going to shoot, that is water soluble, so you know how to do it, without wasting anything... that's what I would think would help to help you learn..