First off, I have a MES 30 and LOVE IT! Top vent with a simple chimney set on the vent solved my minor problems maintaining smoke.
Getting proper airflow / draft is paramount to your success with or without the AMAZN tray along with having it properly burning before placing inside the unit.
At low temps or cold smoking getting a good draft is difficult at best.
Some people, such as Bearcarver, have been able to use their AMAZN tray with no problem at all and don't have anything modded on their MES while others, like yourself, have had nothing but problems.
I believe part of the success or problems stem from location of the smoker in relationship to the prevalent winds helping to "push" air into the intake and "pull" smoke out the exhaust vent. Conversely wind from the opposite direction will "push" into the exhaust vent (backdraft) stifling the airflow and extinguishing the pellets due to lack of oxygen.
A good chimney is the simplest way to improve draft and help prevent backdrafting.
Since you seem unwilling to use explosives to improve you draft........ How about attaching a chimney using a few or several small rare earth magnets? No drilling or permanent alterations required.
Another possibility would be a computer fan mounted in the same fashion on the outside, blowing out, powered by a spare wall wart adapter.
Above all else, DON"T GIVE UP.
Once you are able to go an entire smoke with out having to peek, check, look, test, try, or do anything it will all be worth it!