Well, I'm NOT a regular technician, I only really get involved in cars when there is diagnostic input, or electronics issues ... I'm more of the Boss!! While I've spannered, it's been while racing myself, rather than as a Job. So I try to only get involved when something unusual or new crops up and there might be value in understanding it in much more detail for future benefit. I guess I'm thorough to an extreme and only need to justify that to myself ... of course I'm far from perfect and learn new stuff everyday, and here is a great place to achieve that.
The Business is a Ferrari, Maserati and Lamborghini independent specialist but we also get to see Bentley, Aston Martin, Porsche on a regular basis, with owners other cars (daily drives, wife's, kids, nanny's etc) and take on odd diagnostic work for people who get stuck, especially if they share some link (Audi R8/RS series, Alfa 8C etc) but normal cars too.
The clamp recommendation was based on the most used clamp, and the 200/2000 covers cranking (inrush to crank often exceeds 600amps) and the 200 range is good many of the smaller measurements except parasitic drain, and maybe a few others, but it has such a broad capability. We only got ours recently, having had 2 x 600amp but were regularly missing that extra range, so upgraded and our only regret is we waited way too long to do it!
Parasitic drain is not easy with a clamp, once you learn how to avoid the pitfalls then it's fine, but it takes a while and even now I'd rather use alternative methods (read other threads here). There are plenty of things the 20/60 can do better - jaw size in tight spaces ... but too many more where it fails - jaw capacity too small to clamp a battery cable
We have 2 of the 20/60's and I plan VERY soon to get another 30amp (TA189 that is), I'm not getting rid of any of them, they all have their uses, but the jaw capacity of the TA189 is great, and using a 5, 10 or 20 winding to enhance the resolution means a 6 amp, 3amp or 1.5amp range of great stability can be created (also have a 10 coil for the 20/60 to give 2 and 6 amp ranges)
Purchase the 4 channel and add the extras as you go, honestly don't skimp on 2 channels just to get some accessories you can always get later. You'll be building the kit for years, just like your tool box, best start with the right core unit, and that has to be 4 channels.
Oh, and the Pico team are all genuinely helpful, all been there a long time, so know their stuff.
Hope that's helpful