You know my power kite background .... the biggest thing for my brain to initially wrap around was that I needed to fly from the wrists and not with my arms. That most certainly changes later and your arms get very involve, but not so much for steering. Depending on how your brain processes and learns new information, you may find it useful let your hands sit in a nice low comfy position and 'lock' them there and use only your wrists to fly and steer in forwards.
Once I got it into my head that I turn from the wrists and not the arms like a power kite, it was easy to progress from there. It didn't take me long to lock the concept in my head and when I did get under pressure and revert back to arms I knew I was making the mistake. It may also help to make your rev turns using the same motion as your brake turns from your power kiting - this will put a bit of a side slide onto your turns, but may prove to be an easier transition for you.
As for which Rev ....
I got the SLE originally, then got a 4 wrap frame, and very soon after that got a B series. Now I have full sail and full vent B series for my regular flying with the SLE now doing beach flying and beginner training. My B series full sails carry either race rods or 3 wrap frames and my vented runs race rods, 3 wrap or 4 wrap frames.
If you can afford it, go for the B series - it's a much better investment. If you can't, then go with the SLE, many people started there and many seem to fly them with complete satisfaction alongside the B series. I have flown my B back to back with my SLE with the same frame, line, etc and there is a noticable difference in the experience in favour of the B series. As someone who is still learning many things on the Rev, my SLE will make me pay for less than precise inputs MUCH sooner than the B, which will threaten to make me pay, but is smooth enough to fly through it.
That's just my experience coming from a power background into the world of Rev and what I have experienced .... your mileage and conditions may vary