The tool kit mounted on the back of the press is handy, as you have all the allen keys and the right size wrenches for every fastener you have to turn on the press. However, the press ships with all the necessary allen keys. The ones in the tool kit are longer, dipped in plastic, and have ball ends (easier to use). It's a matter of convenience only. The wrench only works with the special 1 inch lockrings from Dillon. They're not expensive, and the small end of the wrench fits the powder measure adjustment nut. It's faster/easier to work on the press when all the necessary allen wrenches are racked by size in hand's reach.
Get extra toolheads; enough for each caliber you intend to reload. This minimizes changeover time and allows you to leave your dies set for a given caliber. If you're changing the [powder|bullet|load] for a given caliber, all you have to adjust is the powder throw and the seating depth.
Given the choice of spending the $, I'd buy the spare parts kit first. Even though Dillon will send replacement parts with just a phone call/email, the press will be down until that spare arrives. With the kit, you can replace the broken/lost part and finish out the session rather than waiting. The replacement part then goes into the kit for the next time.
Steve
Square Deal B (small primers)
RL 550 B (large primers)
both with tool racks/kits
