Need help using the Rokinon 14mm with a DSLR

I just purchased the Rokinon 14mm for use as an UWA lens with my Canon full-frame. I had previously used a Sigma 10-20 on my Canon crop camera and found I missed a good wide angle lens when I traded up to full-frame. I thought about buying the Sigma 12-24 (the Canon 14mm is above my budget, at least for now) and tried using the Sigma 10-20 with a Kenko 1.4 TC attached as a 14-28mm zoom. While that worked there was significant distortion and vignetting and so I decided to give the Rokinon a try based on some of the positive comments posted here.

The lens arrived yesterday and I have been trying it out and comparing the results against my Sigma/TC combination. After taking several dozen photos I am beginning to believe that I need some help in learning how to get the most out of this lens.

Focusing

I understood, from posts, that I could use LiveView to focus this lens. I did not understand how that would work since there is no communication between the camera and the lens, but I gave it a try. It does not work for me. LiveView is just as ineffective as trying to focus through the viewfinder.

On the other hand the hyperfocal length of the lens is so short (at f/11 the hyperfocal distance is 2 ft) that manual focusing is not too much trouble. Generally I just set the distance at something approaching the proper length and call it good.

Shutter Speed

I have been manually adjusting the aperture to something that seems appropriate to the light conditions (perhaps f/4 or f/5.6 inside, perhaps f/8 or f/11 outside) and using either the Av or M modes to adjust the shutter speed keeping an eye on the exposure metering and ISO in the viewfinder. While this (sort of) works I have noticed that the exposure I am getting seems to be a bit high. When I compare the images from the Rokinon with those from the Sigma/TC combination (which has AF and can talk to my camera) I can see the exposure difference easily. While I can adjust that in PP I suspect that I am doing something wrong here. I should not have to do any PP adjusting to get the exposure right.

IQ

On the other hand there are some very positive things to say about this lens. There is less distortion than with my Sigma/TC combination, there is much less vignetting, the colors seem very nice and, for some reason I don't understand, the Rokinon 14mm seems to be wider than the Sigma 14mm even before I have to crop the Sigma/TC to get rid of the vignetting (it is sometimes too great to remove in PP).

I have also tried noting what aperture/shutter speed combination my Sigma has been using and setting those manually on the Rokinon, but still the combination does not seem to give the same exposure as on the Sigma. I assume I am doing something wrong and, possibly, stupid, so I thought I would ask how people who have this lens use it.

Best Practices using this lens?

What is the best approach to using a lens that does not talk to the camera? Are there any tricks that should be used? Is there anything special to know about using the Rokinon 14mm? Would a focus chip be a good addition? And, if so, why? Just for focusing? Or is there some other advantage to using it? Is there any way to use LiveView with this lens on a Canon? Or am I better off just biting the bullet and getting the Sigma 12-24 and be done with it?

Any help in how to best use this lens would be appreciated. Thanks.