How much spring pressure is too much?

Your actual lift at the valve isn't going to be the theoretical. It's likely going to be about .560-.565

That will give you a rate around 330 open

The spring lunati recommends is 115 at 1.700 and 336 at 1.150 with a 402 rate

That comp spring is 120 at 1.800 324 at 1.250 with a 370 rate.

The comp spring is really lighter than the one lunati recommends which is the same as a 995 comp spring.