When to adjust valves? oil change? On recent motor.

I have about 20 hours and couple hundred of miles on my 512 ci RB. We have had it up to 100 mph and hard takeoffs as well as cruising around town.. It has solid lifters. Cam specs are.

From Ken Heard of Oregon cams.
244/252 @ .050”, 282/290 adv, .516”/.537” lift(1.5:1 rocker), 112 sep, .016”/.018” lash

This is a very good street/strip grind that should make power from 2200/6400 or so. Will need a 3000+ converter and will work well with your compression ratio. Normally I would put this on a 110 lobe separation but with the nitrous and fuel injection I think 112 to 114 would work better.
The heads are trickflow 240s.

When is the time to recheck the valve lash? After a number of miles or time or what use(races). This will be used as a street car but also run on the track for fun.
While I am at it. What about second oil change?. I did the first after break-in a couple hundred miles ago.