I use #6 crosslock snaps (~150lb) with no swivel. I add a short piece of chafe tubing at the crimp crotch on my top shot, as that is always the weak link. I stopped using swivels. I don't think they are needed for most types of fishing I do.
P-line and Berkley make great crosslock snaps. There are much cheaper ones from China on eBay, but the quality is hit or miss.
Another suggestion is a corkscrew swivel. I saw them for the first time fishing Alaska last summer and I loved them once I figured them out. I have not bought any for RP fishing yet as I have enough swivels but will give them a shot once I need to resupply.