Hummm .... I have bo idae about this rack degign now ...
As you said , latger plastic boxes in rack will be difficult to slide in and out . Probably you are correct , I can imagining the tabs will been heavy with a large water bowl and a large boa inside .
You said the rack system design is an open shelf , unlike book shelf . I want to know what's the differents between "Open design" and "Closed design" ?
Closed design will keeps warm in the rack tabs will I guess it's will be better for keeps the coldblood animals .
I will trying to search some data about rack design in net and maybe I can get the best idae for me in these days .
Thanks a lot for your recommends . 
(By the way , the full name of Taiwan is "Republic of China - Taiwan" ; and another is "People Republic of China." . They are different . That's ok .... it's not the point of this topic ..
)
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4.5.0 Boa constrcitor
1.0.0 Morelia amethistina
0.1.0 Python breitensteini
1.1.0 Candoia aspera
0.0.1 Cylindrophis ruffus
0.0.1 Eryx miliaris
0.1.0 Iguana iguana
0.1.0 Brachypelma emilia
Life with scales ! Scale Style !