[68protouring454]

when I road race, i always re pack the bearings and clean the tubes after each race weekend, which is 4 -30 min sessions for practice and qual, and 2 35-45 min races. I always have some oil in the the tubes(with inner seals,which we silicon as well). Never had any bearing issues etc, we also ran our fluid level high but found it to get by the seals and start to wash the bearings out, in sprint races (under an hr) generally with a rear end cooler, you can keep 2.5-4 qts plenty cool.
A floater will absolutely stop knock back, HOWEVER, the rear end has to be straight, we do all our welding with a jig(and a certain procedure) and still get run out to .200-.300 thou, we then heat and squelch till we have under .008. Now once you have a straight housing, now you space your caliper correct and you will have NO knock back.
Most of the time complaints on caliper knock back with a full floater is, either axle run out, or a caliper not spaced properly on rotor.
Now when you get into hard track day, time trial etc use you will now get the rotors so hot the heat gets into the calipers and boils or starts to boil the fluid, which will give you a spongy knock back feeling pedal, now add cooling.
It all adds up to going fast, generally on a protouring car with a d.o.t tire you wont get the brakes hot enough to do this unless you have really cheap brake fluid or race compound pads.
we use gun drilled axles

the zr-1 set up looks nice.