after looking at a cambium saver I decided that I could make my own for less. much less in fact. all I took was a 3 foot rabbit runner from blue water and two non locking carabiners. I took a rappel ring and set it up like a quickdraw with a rappel ring on one side of it. Later on after realizing that a knot would not fit through the carabiner I added my figure 8 and removed the rappel ring fromthe setup. Then it installs and removes like a normal quickdraw. the price added up to 30 dollars as opposed to 60 dollars for a buckingham, and has less friction then a leather tube
Could you post a photo? It's difficult to assess the safety quality without seeing it. For a tree climbing anchor you should use locking carabiners, even then it is problematic using carabiners because a moving rope can open a gate. There are many ways to make a "false crotch", if you take a look at the various fixed and adjustable systems available from tree gear supplier web sites (like Wesspur, Treestuff, Sherrill, etc.) you might get some good ideas to further improve.
I'm strictly in the sleeve cambium saver camp, very easy to remotely install and remove. The 3/4" inside diameter Dan House sleeve is my favorite for 11mm to 1/2" ropes. Friction is much less than a leather sleeve. A little friction is a good thing DRT, it takes pressure off your hitch. The sleeves are also create a very wide bend radius on your rope as opposed to "ring/ring" friction savers. The Dan House sleeve is made from liquid tight electrical conduit, steel coil lined, vinyl exterior. Very rope and tree friendly.
The issue with unsecured connection is by definition it will be remote from you and the roll out connection is very possible.
Also look for some rated steel rings. You will find very few times you need mid line attachment with friction saver in doubled rope climbing. The security and possible decreased purchase price is a nice feature of rings as well. Aluminum will work, but I find they wear Much quicker.