Yes, you can still co-witness your sights when using the Unity Tactical Optics Riser Platform with a Eotech EXPS2.
NO! It will sit too high. You cannot co witness any irons with this riser. It is designed to be used with optics that already have a 1/3rd co wit to bring it to the height of 2.26 (roughly) so you would be able to use their magnifier mount for the g33. You might even have a hard time finding room for the irons with this set-up. This is the trade off for this set-up.
You can find space for an iron sight, it’s just tight… they will NOT co-witness though, in a pinch you can use the quick disconnect on an EOtech (or any red dot that has a quick disconnect), flip your magnifier over, and voila! You have iron sights. Not a perfect solution but it’s an option.
It will not, like the other answer says, the eotech and romeo 8t are already lower third. Best option is offset irons or back up offset pistol red dot.