More efficient way for Cyrillic masks

Dear hashcat community,

I have a question about mask attacks using cyrrilic charsets.

I'm trying to use a mask where I can use both uppercase and lowercase cyrillic characters as a seperate charset.
This way I want to do a mask attack like ?u?l?l?l?l?l but in cyrillic.

First thing I did was:
This performs quite well at almost 11000 MH/s on my 1080 Ti, but does try a lot of HEX combinations that are not actual cyrillic characters.
Therefore I went looking for a more optimised method which skips this non-existing chars.

I came up with the following:
I made 2 charsets which I converted to iso-8859-5.
This way the attack will only use actual cyrillic charsets.
However because of the pipe, performance is horrible (around 430 kH/s) and I can't see progress or resume at a later date.

My question is, am I missing an option somewhere with which I can either skip the non-cyrillic characters in method 1 or greatly improve performance in method 2?
If there is another more efficient method I haven't thought of, it is off course very welcome as well.