the ignitor I like I run is good for that rpm.
all my junk slings a rod or floats a valve before it runs out of spark
been in the 6200 to 6500 rpm range on my junk,its 15 yrs old and has never gave any trouble,been pulling street duty daily.
I run the 40,000 volt flame thrower chrome coil.
never had a reason to try the II & III setups.
maybe you should look at the firecore ready to run dist with a set of the firecore wires. he is a member and sponcer here IIRC.
good result posted back on that one.
I have used 8-9 ignitor I conversion and all have been flaw less and trouble free fixing at lot of smog era mopar ign crap outs.
run it on my 85-318 & 88-440 truck by-passing the stock elct ign, by useing the points dist and conversion.
simple,cheap,reliable