bCNC, There is also a platform version of UGS that I like much better than UGS. There is a new on about to come out that has some wonderful features that I really like. More to come on that.
I use PicSender. It will handle massive files that will lock up when using UGS. It isn’t free but for less than $20 you can’t go wrong. (No I don’t have a financial interest it it). Before you buy it you should download the free test version to see if you like it. Then upgrade to the paid version. The trial version will only carve 1/2 of your g-code so it is useless except for testing it out to see if you like it. Not a bad idea for them to do it that way though.