banana jacks

i bought my banana plugs for my tower speakers i'm making - the pvc is pretty thick stuff in the end cap i'm using - i drilled the holes and set them in - everything fits except if i use both the red and black piece of plastic fitting - it isn't long enough. in the picture you have the black and red fittings (where the arrows are) can i eliminate, say, the black one and only use the red one on the inside of the can and use the nuts to hold it in place? hope that makes sense... sorry for the lack of terminology. will they still work? tell me yes i already drilled my holes...

Since you are using pvc wich is non conductive you could feasably loose both of them. I put the jacks straight in when i do fiberglass boxes, never a problem

why put them in the endcap ? why not on top of the speaker can ?

http://www.wakeworld.com/MB/Discus/messages/3183/308811.html?1142837753

because this is the first time i've built something like this... and little things made a big difference! i slid the end cap and coupler over a regular piece of 6" pipe...so had i put them down through the top - it would have been going through two full pieces of PVC...and i didn't think they were long enough...so like a dumba$$, i though the end cap would be equivelant to one piece thickness, but instead it was about three times as thick. so basically, i'm a rookie and i screwed up. i also ran a 17mm bolt up through the bottom of my light bar to the clamps i bought...and because of the size of head on the bolt, there wasn't really enough room on the inside of the bolt without pushing on a light so i had to put the cans outside of the bolt...and things just didnt fit. it still looks okay... but i only had a limited about of space to work with.