Not all NET's gunk up coils/atomizer heads badly. IME, Heather's Heavenly Vapes, Mountain Oak Vapors, and Backwoods Brew's NET's have all been very clean and easy on coils. The only one I remember that was really bad was GoodEJuice, but I didn't like their flavors much anyway (except Patriot, which was actually the cleanest burning). In fact, I think the only times I've had issues with gunking is when the NET had a lot of added caramel flavoring and/or sweeteners.
That said, there are a lot of beginner friendly RBA's out there. The Kayfun-style would be a good option if you want a tank, but the IGO-L is also a good one to try (RDA). I wouldn't worry about the tightness of the cap, just make sure whatever you get has good reviews and phillips head screws in the posts. The Patriot RDA and IGO-W types are all dual coil, which means you'd want to cover one of the air inlet holes to run a single coil. Dual coils are great and all, but IMO they aren't that much better than a good single coil. Setup is only a little bit trickier, not really enough to be a concern over a single coil.
I would encourage you to try a regulated VV/VW mod before going straight to a mechanical. Read up on the differences to understand why (or why not).
That said, there are a lot of beginner friendly RBA's out there. The Kayfun-style would be a good option if you want a tank, but the IGO-L is also a good one to try (RDA). I wouldn't worry about the tightness of the cap, just make sure whatever you get has good reviews and phillips head screws in the posts. The Patriot RDA and IGO-W types are all dual coil, which means you'd want to cover one of the air inlet holes to run a single coil. Dual coils are great and all, but IMO they aren't that much better than a good single coil. Setup is only a little bit trickier, not really enough to be a concern over a single coil.
I would encourage you to try a regulated VV/VW mod before going straight to a mechanical. Read up on the differences to understand why (or why not).