my bumper has a sticker that gives dimensions for how far a rack may stick out and a max weight of 135 lbs.
However I think it would far better in the long run to build a receiver into the frame below the bumper.
I like the idea of mounting in front of the truck, but on some trucks the transmission and oil cooler may be mounted very and use the open areas of the bumper for venting, so you may not see any difference in coolant temp but the transmission may be heating up. though the real reason I would not carry anything up front is the bugs I would have to wipe off at every stop...
2013 Coachmen Freedom Express 320BHDS pulled by a 2005 F250 King Ranch CC
A rainy day camping is better than a sunny day at work.