My motto is do what you gotta do to get sleep. As long as it's safe then do it. I've coslept with all 3 of my kids because that's what works for us.

Attach his full crib to your bed with one side of the crib taken off. It basically extends your bed, look into my posts I have a picture up of our set up. It's really convenient and is a win win for everyone.

I've been trying the naps in crib and co sleeping method but he only sleeps good in my arms. If I scoot him over towards the middle of our bed he doesn't sleep as well. But my arm get tired haha I know, pathetic. But then I can't sleep because I'm uncomfortable.

I used the rail on our bed and it was fine. No gaps and even if there was I'd be sure to fill it safely or just not use it. But it held up nicely. I just didn't like sleeping in the middle because my son loves to move around in our bed and then I'm squished between him and dh.

Moving the crib in our room with the side down was the last resort because it's not easy. I wanted to see how others were sleeping successfully. But I think the crib might just have to come in our room. I also like being able to put him in his crib in his room because he sleeps well. Night sleep is the only pain since he wakes up many times.

The rails for toddler beds are not recommended until 12 months earliest as there is a gap between the rail and the bed which they can get stuck in making it a suffocation risk. The side sleeping cribs are meant to be good, could you not take one side off your crib and if you have enough room put it against your side of the bed? (With no gaps obviously)

I would just put him to sleep in his crib during naps that way he still knows that the crib means bedtime still