I don't like heavy seas it makes fishing uncomfortable. I use to do lots of comps and you don't have choice on the weather . It is what it is when the comp is on. Back then I had my old 228, no hardtop so she was much lighter and more stable without the weight up top. A bit older now , heavier boat, retired so I can pick my days and only do 2 comps per year.
I have been in some very heavy seas in both boats , never felt in any danger but always in contact with Marine rescue and have all safety equipment including EPIRB , 2 VHF radios ( it is a requirement for comps here) , sat phone etc..
3 foot at 5 seconds are fine heading out square on them trim in make sure the boat is level. distribute weight so boat is level to start with and only then use tab so you are level. trim in enough so the boat slices rather than jump. I would say I would sit on 20+knots and may have to back off every now and then on the bigger closer together waves. You will use more fuel but it is only gas and only costs money , who cares. 6 foot and 5 seconds is a bastard to head out in however 6 foot and 9-10 second is fine .
On the way back we always have seas behind us as long as they are dead square trim up and ride then , I would say 25 knots there but again boat must be level, never trim in on following seas and avoid using tab , use very little to lever if you have to.
On heavy seas at comps I would follow a 45 footer out as they flattening the sea for you .