Semi-urgent oversparge question

Just a quick question... and hopefully a quick answer.

I have just a bit over 7 gallons of wort boiling away on the stove right now. I was shooting for only 6.5 gallons of total runoff from the MLT but I obviously made a miscalculation somewhere and ended up with an extra .75 gallons or so in my kettle. My question is this...

Is there any significant harm in just boiling for an extra hour or so before I begin my hop additions? I figure this will allow the total volume to boil down to ~6.5 gallons which is where I wanted to be in the first place. This will make for a total 2 hour boil. I'm doing the boil on my gas stove which has a pretty beefy "Supoerboiler" that works quiet nicely for doing a full boil but it's not a very aggressive boil so I can't imagine that the extra hour will have any terrible consequences. Am I wrong?

Thanks for any help you can provide.

-Brian

There is no harm in a longer boil. It probably will give you a darker beer.

You might want to check your gravity NOW to make sure that you are on target to hit your planned OG - if that matters to you.

I regularly boil 90min, if I'm doing a very strong beer I'll boil for 2-3 hours to get my target volume.

So, I wouldn't worry about boiling for a couple hours, then adding your hops in the last 60min or whatever.

Great! Yes, I've checked my gravity and adjusted for temp and the increased volume and I seem to be on target for my O.G. so, hopefully no worries there.

Thank you very much.

Just to confirm my calculations... if I am shooting for 6 gallons of wort at an O.G. of 1.053 @ 68 degrees, what should my 7 gallons of boiling temp wort be at for gravity?