I know not about the Zeus replacement, but do not need to do so and I do not use copperslip, why - here's my tip:
I use the stuff you put on your lips to stop them from cracking in cold windy weather - "Lipeeze" is one such brand name but there are loads. WHY?
Because a dab of this water resistant vasaline/silicon based product on the screw threads and a dab on the rubbers will stop any siezing-up of the fastners - even in that horrible area down under. I've ridden in monsoons and have the bike stored in freezing sub zero temperatures in winter here. The result has always been super smooth swift off and on job. And it's cheaper than copperslip!
It will not of course rectify the stupid design/positioning of the panels interfering with the basics like oil changes and battery charging.
By the way - I once read a post on here that Optimate do a plug that fits into the external electrical socket, thus eliminating the side panel problem when battery charging. IS THIS TRUE??
The reason I ask is that here in Switzerland nobody knows anything about this option. How much does said plug cost (what's the product number) and where can you buy it from in UK. Any info gratefully awaited.