Having the Indy block drilled for individual lifter oiling. What size -3 or -4 or ???? And was thinking about a #6 main line size. Thoughts.....
Thanks

-3 and my whole plumbing is restricted/fed by a .050 nitrous jet

OP, what type of rockers are you using, ductile iron, extruded aluminum or full roller aluminum?
If aluminum roller rockers use a smaller restrictor like .040 or so

T&D rockers on a common shaft.

Call T&D for there recommendations!!!!

-03 AN here too. I used an 0.040 flare jet in each lifter bore feed line. I had about 65psi of oil pressure priming the pump with no lifters in the bores so I figured I was pretty safe if I launch a lifter. I tapped the holes 1/16" NPT.

Do you guys think the -6 main oil feed line to the distribution block is to big then?

Absolutely
Run the same size feed line to the distribution block as you run to the heads, unless you already ran it

If you haven't started the process yet, send the block to westin, or industrial boring and have normal lifter oil galleys drilled into the block. The lines, fittings, and time are more than just having the galleys drilled. JM2cents

I reread your post, I assumed it was about rocker arm shaft oiling, not the lifter galley
Ignore everything I posted, I have never done what your doing

Is there some advantage to individual lifter oiling ?!?!?

This block I have has no oiling to the lifters.

Your fittings would be 1/8" before being compressed
but you only need about .015 per rocker it be good..
so if you figure what .015 per rocker anything bigger
per rocker adds up to a lot.. I kept going smaller on
my SB stuff to get it right.. it takes very little oil
on the TD rockers to have them live..all I run is TD stuff