Since you have 500 and roller cam and lifters, you should be fine to wait for the next nice day you have, take to the freeway and nail it on the on ramp, (from about 10-20MPH) and hold it till you hit about 80, (or merge speed) merge, drive a few miles, get off the next exit and back on the ramp and do it again. Letting the billy-goat shift from WOT will be fine.
Repeat a half dozen times, then change the oil to what you like. I run dino oil with ZDDP in my nailhead because it is flat tappet cam and stock rockers. But I will likely run a synth in my 430 (built much the same as yours) after break in.
Seating the rings correctly requires a few strong pulls once fully warmed up, and a few minutes of recovery time between pulls.
It allows the rings and walls to build sufficient heat that the peaks on the walls from honing are taken off and the rings tempered a bit. If you "baby it" (for most of the engine life) the harder rings (as in what have been used for a while now) sometimes do not seat as well. But we are also talking about a car that is not driven a lot of miles as would be in a daily driver, so the issue is not anything to get worried over.
Similar to bedding breaks, or hardening gears in a transmission or rear end.
A lot of old owner manual "break in procedures were more about getting the person familiar to the vehicle.