Finding a Schick repeating razor in very good condition is very hard. For inserting the blade I use a key and insert the blade from the opposite side.
Now to motivate your hunt, a teaser.
Xpec, Tabula Rasa and Kiss My Face and my recommendations.
More importantly, keep your routine as simple as possible. Is the only way to find out what might be the cause of the problem. I've even had the brush being the problem ...
Use more product. A lot more. I spend a while loading hard soaps particularly with boar hair brushes.
You can wet the surface of the soap first thing when setting up to make it easier and, imo, better.
I would say AutoStrop and Probak got into Gillette, more than all the way around. At least Gaisman did. http://www.safetyrazors.net/DEBladePage.htm
Here is a thread I found useful about AutoStrops and the blades each model takes http://shavenook.com/showthread.php?tid=2035.
These razors don't...