I believe the taifun doesn't require you to empty tank to access the deck. I don't have one so idk about the center post issue. I use a Kayfun 3.1 and just rewick at the end of a tank....
Something like the big dripper may interest you? It's a rda with a 5ml tank on top that you use to auto drip.
I apologize for the lenhy post, but I'm cutting an pasting a post I made at another forum I frequent
I've compared the following:
Erlkonogin (auth)
Erlprinze(auth)
Aqua v2(auth)
squaper(auth)
Taifun gt II(auth)
Kayfun v4 with 4s kit (tobeco clone..regarded as close to auth as anyone)
Not engaging in clone v auth discussion, but for the record it was a gift.
Also in full disclosure I prefer a very dense, warm, flavorful vape and a loose draw as my opinions are based on that.
Out of the box the erlprinze was and is my favorite fairly loose draw, very flavorful and a good thick vape, building on it was very easy kicking it however is a learning curve.
The erlkonigin surpassed it once the center post was changed from its stock to available upgrade, giving it a slightly looser draw than the prinz, more flavor and vapor
Closely behind was the aqua v2, these top three are interchanged regularly. The aqua is basically like building the erlkonogin twice as its a dual coil, giving the vape a denser texture, and fuller flavor, however it does require ore power to push but its worth it.
Those top three I also find to be more aesthetically appealing than the others as well, lighter, smaller with more than ample juice supply.
The taifun v2 after adding a nano cap and tank would be the next enjoyable, simple build, simple fill. Almost identical to the v1 only much improved airflow. Out of the box it was fantastic, just a little to tall for my taste
The kayfunnv4 was a gift after field testing another product.
Without the 4s kit, I felt no difference in vape experience from the 3.1 muted flavor and anemic vapor. Throw in the 4s kit and who, other than its appearance, which is a manner or personal taste, it was great. 35w no dry hits, warm vale, no flooding.
The sqr... ehh I can see it being enjoyable as it is rather similar in vape experience to the taifun, to me its temperamental to build on, wicking made it a dry hit machine for me, and its huge. Way out of my aesthetic range. Out of the above tanks all can be built without emptying tank. The ERl does require a trick since it was not built with the intention to, but its easy.
Again these are my experiences and my personal taste.
YOUDE GOBLIN RTA V1.2 *I have 3, and love em* 
