Not used Werkstatt, but I really like LimePrime. Very similar to SRP to use tbh, but if anything goes a little further and smells better!
Not really duck.
I own al 3 products actuall but anyway. I see LP on Prime as 2 different products. I would never use LP as a cleanser only because it's a little oily and that itself isn't a great base for topping but... used with the right pad 3m yellow for eg it can offer some correction by machine and I would only use LP by machine, there are better products by hand.
LP is almost a cleanser/light polisher and light glaze in one. You would go straight to LSP after LP although I wouldn't use a sealant due to the oils in LP.
Prime or primes strong, I use the later is probably the best cleanser on the market, the dirt it'll pull from paint even after polishing is incredible but it's a cleanser and awesome base, i'd always follow with a glaze, blackhole or EZ creme glaze (both acrylic) then your LSP of choice.
Use prime/strong on glass, lights, shuts for fantastic beading and sheeting. It's actually lasting just aslong as my dedicated windscreen sealant.