2" Duo Band Thickness

gammerpc

I have this 2" Duo Band Filter for my ASI2600MC Pro and would like to know the Glass Thickness so that I can add a Clear or (L} Filter to be at the same Focus.
Also what would be the Best Filter that I can use for this?
I am using the ZWO Filter Drawer with M54x0.75 Thread mostly because no one in the USA has the M42 version.
I already have the second ZWO Filter Drawer.
Also how do you set the Settings in MaxIm DL 6 for the transmission "OIII line 486.nm1, 496nm and 501nm. transmission at Ha line 656.3nm"
Do we add the image 2 times one for Ha and one for OIII or 4 times 1 for Ha and 3 for OIII?
Thank you

Tech@ZWO

the Glass Thickness
=>5mm+2.5mm

gammerpc

Thank you, so the frame then is 2.5mm.

gammerpc

Does ZWO sell a 2" Clear or (L} Filter that would match the ZWO 2" Duo Band Filter?