Hi.
ummmm, depending on a lot of factors you will be able to make the HDR you need using fisheye or not. You first need to know what kind of HDR do you need: Really precise unclamped HDR just for lighting + Backplates? Really big HDR?, Quick HDR you can make on set in 2min? you need low Hemisphere?, etc...
For example: Let's say you want a digital "copy" of the day/hour you shoot your HDR. You need really precise and unclamped HDRi for lighting purposes, you want to be able to make the HDR inside a 5-10 min window tops (otherwise you can't make good sunset HDRi, clouds will move a lot, etc) since you need 10-15stops ND filter to get unclamped HDR and something like 20-24 EV you will be shooting at V 30seg+ a lot (this impacts drastically the HDRi). But using 10-15ND filter introduces a really big bias on the images you get (heavily colored vignetting) , so the post-processing part of this kind of HDR become really complicated (you can see it on the Unity document), time consuming and introduces random failures (some of the HDRs just wont work). In my opinion if you need/want perfect unclamped HDRi just for lighting (most of the ones from the internet are really, really bad to be honest) it´s better to use 180º Fisheye because otherwise you won't be able to capture all the images you need on time.
But if you don't mind if the HDRi it´s unclamped and you only need a beautiful/high resolution sky, don´t use ND filters and use medium format camera (or new generation DSLR) and 12-24 lenses, you can paint by hand the dynamic range you clamp on the sun during shooting to get a really high resolution HDR, it´s not 100% precise but if you do it right nobody will notice the difference.
You can use this calculator to decide which camera/lens you want to use:
http://www.hdrlabs.com/tools/panocalc.htmlGetting really precise/unclamped HDRi and 32k it´s almost impossible, even using medium format cameras or new generation DSLR, so keep this in mind if you are new to HDR capture.
About the "unity" method, they take +-30º because they want to be able to remove people/traffic from the horizon but in archviz we usually don't even want horizont so you can make it using just 1 rotation (3-4 positions) + Nadir and you can get unclamped HDR using ND inside the 5min window. This method it´s really good but will fail sometimes and usually requires more post-work so it's not rock solid, you can't do it on a set and risk the HDR for example.
About Pano Heads, if you need a versatile one you can adjust to be used with any lens i recommend you Nodal Ninja, if you want the easiest one to use you can get the 360Precision
This is just my recommendation after making lot´s of HDR but i can be mistaken ;) so you need to experiment a lot in order to be able to get the HDRi you want and be able to make it consistent.
Best.
