Sounds like you're already able to handle them confidently and won't freak out etc, so I'm not really sure what you need.
I don't know you well enough to give you advice, but it sounds like if I did I'd probably say something like 'Stop overthinking it and go buy some Adders and Red-bellieds'.
Keeping calm or semi snappy pythons probably does more harm than good; it gets you into the habit of taking 99.9% risks, because on the 0.1% of the time where you get bitten you don't think anything of it, and if you take these risks and never get bitten you figure you're doing everything perfectly. I often spend hours tending to hundreds of pythons without being bitten, but I'd never work with elapids with the same level of caution; I'd use a very different system which would take a lot more time, because I'm not trying to avoid 2 minutes of laughter and a speck of blood, I'm trying to avoid something potentially catastrophic. Something that absolutely constantly tries to bite you can train you if you say something like 'If I get bitten even once, I fail and have to start again, and I need to go a year without a bite before I can get my Red-bellied' or some such thing, but the problem there is that you're probably going to get your Red-bellied and it'll be a sweetheart, you'll be able to freehandle it if you want to, you'll be using a very different style of everything from handling, feeding, etc, so everything you learned was pointless, and then one day it bites you. For the most part, you just need the right mindset, which people generally either have or don't have. The actual skills required are negligible, but that's what people focus on. If you watch someone play with elapids you can immediately see if they're someone who should never again play with elapids, someone who could keep them as their first snakes, or someone who doesn't really fit into the usual categories (most people are in #1 or #2).
I'm not really sure what you're asking. It sounds like you just want someone to say 'Sure, you're ready, go for it'. It's not like there's some secret 'If they twitch their tail to the left in the afternoon it means they'll coil up like a spring and launch at you, which you can convince them not to by closing your left eye and holding one hand in the air' type thing. They're just snakes, it's not really rocket surgery. If you have common sense, which you probably do since you've caught good numbers of them without being bitten, and any experience keeping snakes, you should be fine.
Again, I can't be sure about anything to do with you without knowing you better and I'm just making some guesses about you, not giving you recommendations etc /disclaimer