Nice looking batteries. The M6 studs appear much better than the M6 threaded hole cell terminal from my viewpoint. I have noticed where some are placing an aluminum washer around the M6 stud battery terminal to give additional connectivity. I don't know the measurements of your battery terminals. If this is something you may want to try, check your terminal measurements and maybe these will work for you?
I have the same batteries on order and will probably try the aluminum washers if they are the right size. I will also probably will use some DeoxIT battery grease (or something similar) to help the connection between the battery terminals and buss bars along with cleaning the terminals with some 1000 grit sanding paper or very fine file to the clean the terminals.
Still researching ideas at this point...
https://www.amazon.com/dp/B078JT8K1...olid=3DRR8NOQXOKHM&psc=1&ref_=lv_ov_lig_dp_it
Are the M6 studs stainless steal?