Just pencil-modded mine to about 0.85 MOhm getting 2.99 Ghps each.
Both sit in front of a big 120mm fan.
Is this okay or should I go lower in terms of Ghps?
As long as you got that fan there and it isn't hot to the touch you are probably fine.
I'm not familiar with pencil modding, will this make these run a lot hotter to where a fan is needed. My Red Furies are running super cool to the touch.