I like the Magpul slim handguard so much that replacing the front handgard cap is not a big deal. It's really not that hard and doesn't take much time. When I use a free floated rail I don't use a barrel that is drilled for a front sight tower. I don't like the front pin cut showing. It's easy to replace a barrel.
I had been buying Delton mid-length lightweight barrels from JSE Surplus. The barrels came with the sling swivel and front sight parts. They just have to be installed. The barrels come with the triangle handguard cap. I would just replace the handguard cap and not install the the front sling swivel.
The same barrel from Delton was $5 more and just a little more for shipping, But it didn't come with sling swivel and front sight parts. Those parts were extra. I contacted Delton and asked if they could install a round handguard cap on the barrel. I was told yes and that there was no extra charge. With shipping and the front sight parts the barrel cost about $12 more then from JSE.
When the barrel arrived it had a triangle handguard cap and there was a round handguard cap in a plastic bad in the box. I called Delton and asked why they had not instaled the round cap. I was told that it was a mistake on their part and that if I shipped the barrel back to them, they would put the round cap on, but I had to pay to ship it to them.
I told the nice lady thanks but no thanks and just replaced the cap myself.
This was the build.
I know that if you don't have the tools it's not so easy to change parts, but most of us know someone that has the tools. I have a lot of friends that stop by.
If you don't have a friend with AR tools your local gun shop may be able to do it for you.
Every rifle I have built in the last two years, I have used slim handguards, or a slim, or ultra slim rail. But the other night I did build a M16A4 clone for a friend and used a knights Armament quad rail that the Marine Corps used.