I like using eq basket screens, especially compared to dome screens in a wand, as well as elbs but I am not as fond of the maintenance required for them, compared especially to a flat screen. And the eq basket mesh could be a tad looser for my preferred grind.
To be fair I haven't actually had a chance to try an 18mm dome screen yet. The stem/screen part of the equation is really the only part of these vapes that gives me any pause at all, but because it's 18mm it should--well I really want it to work out for me.
First, you will of course get perfectly functional stems with your Zion, and the dome vs basket issue isn't really a big deal. I'm not sure whether screens will arrive inserted, but if they do they will almost certainly be positioned right at the shoulder of the joint. You can push it down further with a dowel or in my case, the barrel of a ballpoint. It requires some force but it's not difficult. If you do this, the screen deforms slightly so that it is almost square with the sides of the glass, so the groove around the edge is shallow and doesn't catch much material. The important point is that you can adjust the screen position.
You'll be pleased to know that Zion screens are a larger mesh than the elbow screens. They do start to clog a little after a while, but how quickly depends on your material. Unclogging is simple for me: simply dip the stem tip into ISO for a few seconds, swirl, brush, dry, and it's done.
Your own stems and connectors are tricky because the Zion uses a shorter joint than the ISO standard, which will sit on the bowl screen with a loose fit and an air gap. Those last two are undesirable and
@RastaBuddhaTao actually warns against the first. Having said that, if you are careful you can make them work. Some will have less gap than others, which affects performance a little. When I originally experimented with this I felt that the performance loss was barely noticeable, but since then I have found combinations that definitely were affected. Everything was usable, however.
The controversial point here is using something that makes contact with the bowl screen. The design of the Zion is such that this screen, given enough pressure, could be pushed out of position. If that happens—
RBT can correct me if I'm wrong—it will not be covered by the warranty. I know enough about the Zion to be certain that this sort of pressure is the
only way that screen will move, so how much risk are you taking when you do something like this? As a beta tester, my job is to find out this sort of thing. I simply inserted my finger and pushed, much harder than I think anyone would under normal use. I couldn't feel any movement. My conclusion is therefore that the risk is minimal
provided you don't apply force. It's your warranty, however, so it's your risk. I accept no responsibility should you move your screen.
By the way, anyone looking for a stem or connector to use with the Zion should not rule out the local shop. I went to mine and looked through their 18 mm male/male connectors and found one with the right joint size, so they're out there. You don't need to have seen the Zion to find one either, since the joint is obviously shorter. If they're all the same then they are almost sure to be ISO.