@GOOREGON
With the Solo stem mod it is key to get a seal between the bowl of the Solo stem and the bottom portion of the herb chamber that you seat it in so that it will lock into the bottom stainless steel heater screen.
The Solo bowl will need some silicone around it to properly seal into the bottom piece of the OEM chamber.....which it will nest into.....if the walls of your silicone tubing are not thick enough to fit the silicone wrapped Solo bowl into the bottom of the herb chamber snugly then you can wrap teflon tape on top of the silicone until you get a snug fit.
I just tried this myself earlier today but have not yet tried it out to see how the much more snug fit into the bottom of the herb chamber translates into any added performance - I will either edit this post or post again (if too much time passes before I try it out) as I have to run to the store and get a couple things done before I vape later.
Also the hole at the back of the Apollo should be plugged to decrease air flow. Some large diameter silicone can be slit lengthwise and slapped onto the side to further reduce airflow......but shouldn't really be needed.
When you seat the Apollo tube onto an 18mm male end (at your bubbler) or if your have some sort of male end attached to the other end of the tube to mate with the bubbler then even without the Apollo attached to the tube/Solo stem combination you should be seeing a decent amount of draw resistance already as a result of the smaller Solo stem/bowl diameter and the o-rings that help seal that combination.
A reduced flow rate is critical for achieving large clouds. I would also pack the Solo stem at least halfway or more (depending on solo or group usage) and I wouldn't pack the OEM bowl any less than halfway full with a slight tamp to densify the puck a little and help reduce airflow.
Also, try to let it heat up for about 5 min before throwing the load into the Apollo. Either turn it off and then back on again after the first heat up period - or put it on setting 10 for a few more minutes after the first heatup (or change the default heating time).
Then drop the temp from anywhere between 4-6 and let it stabilize a little (either wait or start using it and the temperature will decline on its own as it is used) there should be plenty of vapour production at this point and as the temp drops to level 4-6 then as the vapour production declines you will have to boost 5-15 before your draw (and continue boosting through your draw).
When the Apollo is producing the best vapour it will be very hot on the back end and the aluminum backing plate should be too hot to touch without burning your fingers - although still not as hot as the OEM herb chamber.
You will definitely get a flavour change as the herb nears combustion. The more water you put it through - the greater the lag is and the more care should be taken to stay on top of the taste change to prevent combustion upstream to the bubbler mouthpiece where what you are tasting might be a couple of seconds away from the vapour production at the heater end.
I hope this helps.....but if not then maybe PM me and we can discuss further what might be the issue.
(as I said a portable sublimator ... 5 minutes and you're finished 
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