Sorry for the delay. i got in a 40 HQ container today of goods...fun unloading!
I want to be straightforward, the backplate isn't my design. In fact I get it from a LARGE OEM company that makes goods for a WIDE variety of the big and not so big names in the industry. I have some plate ideas but they are back burner because I have other cool products that will deliver more bang for the buck (real use to a diver) than another plate design at this time.
I've had plates these folks have made for a while now in my personal inventory of kit and they have held up VERY well. I have assumed they are made of 312 SS, I will confirm and let you all know. They sure haven't rusted...and I don't really wash my gear and it lives in Georgia....
The extra slots you asked about I have only seen used in a side mount rig. Before anybody asks, NO..at this time I am not planning to market a side mount rig
The finish is solid, not jewelery level by any means. The slots are not sharp like my 2000 Halcyon plate that was a real webbing knife (but their current plates are a thing of beauty...with a thing of beauty price tag! ), but not the most rounded I have seen.
In short it is a solid and excellent piece of kit, without the frill and usual accompanying high price(mirror polish, laser etched branding etc.) It is also a HUGE bargain.
Best,
Chris