I've been brewing a lot of DIPAs and have been boiling as large a volume as I can. Next purchase will be an 11 gallon kettle, so I can do full boils. Right now, the most I can manage is about 4.5 gallons in a 5 gallon kettle. Never have any boilovers, but I am mindful of my wort and my gas stove is pretty sensitive.
There is no way hop utilization is where it needs to be for hop bomb IPAs, with a partial boil. Even with beers that don't push the hop-bitterness-envelope, you could cut back on your hops to achieve the same bitterness.