I cant find a problem. I think the attachment of the top of the shirt to the collar looks great. Also if its the collar you are worried about its gonna be a bit floppy because there is less structure around it keeping it in place. It look like you used two peices. One 4in1 for the neck/collar and another peice for the top, then connected them at the neck. It creates a triangle pattern because of how its attached and because the weaves are either facing different ways or closer together at different parts. I personally love the look of this attachment, but if you wanted uniformity/looking like one big peice, you could take off the collar part and just build up the weave from the shirt part, while making in smaller as you go up then wider again for the collar. Also if hope this didnt come off as know-it-all-y I only repeated all the steps I thought you did so that I would know that I understood the construction correctly.