hi Time ,
just some constructive notice ( in my mind they are constructive ) :
1/
glass door on the side is great for vision , but like you said with end glass loading is easier And you will have less smoke going out cause smoke go out by the opposite side of the batch loading door .
2/i don't understand or and don't see what you mean about chet portal sorry .
3/
That is for me normal , because the draft is created by the temperature , so , at the beginning there is not enough temp. so , there is not enough air sucking for combustion ... in an classic wood stove that's the same way at the start
4/
Did you try to start in Top down , because top down is THE solution in any condition to fire the stove in the best condition . i will explain it quickly for those who don't know yet . ( i con't know if you use top down or no , start in top down down at the back could be better , in my mind that's look to be better ) .
Wood is 80 % of gas and 20 % of material ( coal that you see after seeing flame in the stove is this material ) . So the 80 % will be free by temperature , starting at 150 , 200 °c celsius ( 302 °F, 392°F) , to 900°c,1000°c ( 1652°F, 1832°F) . If you start fire at the bottom , you will start to pyrolysis wood but there is not enough temperature to burn gas ( gas have to be hot to burn ) .
In top down the radiation and contact of the fire at the top will fire the wood under , if you look at it , you will see that almost the all smoke will be suck by the fire who is beginning , causing the the smoke going hot and then burn ....
There is a major effect more than minus the pollution , at the beginning of a wood fire , there is some acid creation like acetic acid that could destroy easily iron . In way to destroy acetic acid fire have to quickly pass the 440 °c (824°F) the dew point of acetic acid is 118°c ( and more of that fire have to pass quickly the 60 °c ( 140°F ) to stop water condensation ( dew point of water ) .
So the goal is to achieve the hottest temp. in the fire box in the smallest time , in way to destroy acid and stop water condensation , by the way top down help to achieve this goal .....
I rebound on your conclusion to start fire at the back , that is in my mind good solution because all smoke have to pass in the fire , in the other side firing at the beginning let the smoke goes in the riser with less temp. and don't burn so good .
In my mind insulation of the ceiling of the batch could be great to up temperature ( this is the solution recommend in kachelofen construction ) to do this you can make plate with vermiculite and fire cement ( sorry i don't know the English name ) , in the 1/5 proportion ( 1cement for 5 vermiculite ) , with the minimum of water ( normaly you feel the mix dry but that's normal ) , you'll put it in a mold and press it ( you can put two time volume mix of the volume's mold ) .
A 3 cm of insulation is the minimum to have a real effect (like in house insulation
3cm is giving high effect after that you take small effect each cm , but i don't say that's not good to have more of 3 cm
i speak about effect of insulation ) .
In my experiment , i do like this .
1/ dry mix
2/ press two time the volume in the mold
3/ cover 24 hour with plastic to keep to fast drying
4/discover and let dry 1 week
5/ put in a hot situation ( in oven for example or directly in stove box ) but starting with a small fire and making a bigger slowly to avoid failure in panel
Know i make small panel max 20 cm large if they are 3 cm thick , with sicker panel you can make larger panel without failure but longer drying is need.
Those panel or better than 100% press vermiculite, in the wall of fire box , because 100% vermiculite break quickly with wood impact , the mix with cement won't .....
don't put more than 2/5 part ( 2 time cement and 5 part of vermiculite ) because yes you'll have harder panel but the conductivity will be higher too , and you'll won't have insulation at end .... just a protection that's no the goal ...
Hope that's will help you
Fred