switching to para setup, got a few questions

I've got a century R1A1 (I think that's what they call it) that I'm turning into a FrankenFal by switching out the stock lower with a para lower from DSA. I've got all the components switched over, but it seems like I'm having some fit issues. Before I start attack things with power tools, I thought I get some advice first.

1) Managed to swap out all the parts from my standard lower to the para lower, but the hinge latch is giving me some problems. It doesn't seem to want to latch when I try to snap the upper and lower together, almost as if the hook on the upper doesn't come down far enough for the pin on the lower to slip over and lock (I'm using very technical terms here, obviously ). Plus the latch itself is harder to move back and forth on the new lower than it was on the old one. I've considered filing off a little from the hook on the upper until I can get the two to lock together....good idea? bad idea? Could the stiffness of the latch moving somehow be contributing to this?

2)Tried sliding the new bolt carrier and dustcover onto the upper and both are binding something fierce. To the point where I have to hit the bolt carrier with the handle of a screwdriver a few times to get it to go all the way down the receiver. Could this be because the parts are so new and just need breaking in, or is this something else? I mean, I really have to whack the bolt carrier a bit to get it all the way down. I was considering putting some JB bore paste on a buffing wheel for my dremel and polishing the grooves on the receiver and the rails on the carrier, but again, I wanted to make sure it might not be something else before I start applying power tools. The carrier seems to be binding up most towards the rear. It'll slide forward pretty nicely until the back of the carrier slides into the grooves, and that's when I need to start hammering

3)Managed to get the bolt into the new carrier and now it seems like there is no way to get it out. The bolt slipped out easily in the old carrier, but the new one seems different. Just eyeballing the two side-by-side it looked like the back of the para carrier is thicker and the hole that the pin on the bolt fits in seems a little smaller. I didn't use calipers so I don't know for sure. I mean, the bolt is in there, and it does seem to ride freely back and forth, so should I be overly concerned about this or just leave it?

Sorry for the long post and thanks in advance for any help

With the breech block, depress the firing pin extension before pulling up on the breech block and it may come out of the carrier easier. I've never met one I couldn't take out. Anmd some were very tight. The old parts fit easier possibly because they broke in together. Remember these do have some degree of weapon tech fitting required. Checking headspace may be required too. You should be able to take all the folding stock parts off the new lower and put them on your old lower. Just look at them. That would sort out your lower fit problem. I don't know if one's metric and one's inch. That could be the problem too. You will have to look for binding spots in the Carrier to figure out why it won't travel freely in the upper. Some minor stoning my be required. Like you figure, agressive power tools should be avoided.