Switzerland Portomarken Zum Db Vs E

The postage dues have a lot of subtle shading differences which make them interesting to sort through to differentiate.
In the 1889/93 D series, there were two versions made, a) light green and an b) olive green, both with carmine numbers. This was the end of the shield and cross type I imprint (KZ1). The D series also introduced a 3 centimes stamp, which you will only find with Type D for the Zum 15-22 porto series.
The 1894/96 type E series is also listed as olive green in the Zumstein catalog and did away with the 3 centime stamp and the 500 centime stamp. At that point they switched to the KZII imprint.
Could someone clarify for me if the colors are essentially the same for the Db and E stamps and the only differing factor is the KZI or KZII imprints?
Do I need to treat these two series pretty much like the Zum 66-71 C&D Standing Helvetias and it's all down to cross and shield imprint types for 17-21?
Obviously postmarks from prior to the E series help clarify but not ones during and after the E series timespan.

Google Schweizer Briefmarkenkatalog and try to find them.

Yes, I think you are correct. Collor's are the same but the imprints are Type I or II. If you collect used ones, then the cancelation date may also help you. You can also use this online catalogue if you want: https://www.ok24.ch/

I love the OK24 site, but the examples for the Db and E stamps look like two different colors in the same Db and E examples they provide. Still not fully sure, but will likely try to treat these like I do the C and D Standing Helvetias. I'm trying to find the non-postmark version, but am first trying to fill all the holes either way.