... 1) you do not need an arbor, to hold the needle-rollers in place during a rebuild; just use a light grease; not Vaseline which at room temperature is barely grease. It is called jelly for a reason...
I also use axle grease to hold the needles in place. The Arbor Tool is nice since it also holds the thrust washers in place and is hollow to aid in getting everything in the right position before installing the countershaft. Plus the tool also only costs $13. I've also rebuilt A-833s without the tool, but not anymore.