Recommended Oil change interval with Oil Cooler left intact

[ZPWR]

Hey yo. Just wanted to pick your brains on the appropriate oil change intervals after having an oil cooler installed and leaving it intact each oil change. So basically the idea is not taking it out to drain during oil changes.

Already read up into a few threads here about some differing opinions about oil changes especially with an oil cooler. One side suggests leaving the cooler intact as fine during the drain and refill cycle. Another side suggests taking it off every oil change interval or atleast 1 in 3 oil changes as a precaution. While another suggests fitting it upside down for ease of draining - which apparantly can cause problems with the dipstick readings.

So just want to 100% clarify this if possible. Oil changes WITH the oil cooler intact - What would you recommend?

I've been sticking to 5000km or every 6 months at the moment. And using Redline 5w-30.

While we're at it. What should the dipstick be reading when cold? I would guess near top H mark right?