Need a little help. Box design

[DizzleDizzle]

So I got my 4 pvc and I'm ready to flare it and finish up sub enclosure. 

I have a couple questions. 

1. How important is it to flare the port ends?

2. How do I calculate port length including flared end sections?

3. How much space do I need between the ports and enclosure walls? Does it matter as long as it doesn't touch? I have to make the ports 12" long and box is only 14 inches deep. So excluding wall thickness that leaves me maybe a 1.25" clearance. Thats before flared ends are added. Unless I

include the flares in 12" total length.

 

Here's a couple pics so you get the idea. Some are missing so I'll add more tomorrow dont know why I didnt get any of the front.

[DizzleDizzle]

Got the ports made and flared didnt like the flares so redid them. I'll update one more time when enclosure is finished.

 

 

 

[DizzleDizzle]

So im pretty sure I'm mainly talking to myself at this point but if anyone knowledgeable sees this I could use some advice.

So I made the ports at 12" including the flares, I did not make them any bigger because they were so close to the back wall of enclosure. I read a post that said the port needs to be atleast the diameter of the tube away from the back wall or else it will affect tuning(lower).

I am confused as this is the recommended enclosure design from manufacturer. Even though I am sure this box will sound great there is too much iffy shit going on here. What should I do go ahead and use it and figure out tuning after or build a new  enclosure?

Also I will be overpowering the subs eventually and did not account for this when designing and building enclosure. Please advise.