Marie is right.
Tech c-cards are not a prerequisite for CCR training.
As she says, you are just limited to NDL.
Before I thought that it was better to have a tech background in order to learn CCR but I changed my mind and found out that students with limited or non-existent deco knowledge are better and safer students.
How do you come to that conclusion?
I'm not saying you are wrong, just want to understand the why.
Most ccr divers I know have an OC technical background, and the CCR was an extension on technical diving (reduce gas cost, extend range/depth). With some of my friends and me having Normoxic (or in the past full trimix) was a requirement to be able to take a CCR course (GUE). Background being that if you bail out you need OC experience to solve the issue.
On the other hand you also see OC tech divers taking CCR and then quite fast (maybe too fast) start doing the same (or harder) dives than they did in OC, not understanding that you really need to do babysteps again in the CCR before you start doing anything technical.
Anyway totally off topic... just curious.
@ the OP: Not much to add but:
- Focus on network: It's much easier to and more fun to dive CCR if you have CCR buddies. The easier part being joint training and practice, a joint spareparts pool and buddies who actually know how a rebreather works, the latter because diving in mixed team (oc/rebreather) limits what you can do with the ccr.
- Testing units: Not so sure, probably you would be able to organise some pool tests with different models, but you are a beginner and don't know what it important for you yet.
- 2nd hand: You reduce cost, but increase risk (failure or cost). Only if you really trust the previous owner.
- Local trainer: Get a local instructor. He'll fix point number 1 by introducing you to the network. Next you always have someone to reach out to if you have questions down the line. But make sure he's good!