That does seem a little light on the hops, but I like hoppy beer. A 90 minute boil is not hard to adjust for. If you know how much you lose in an hour, do the math and plan to collect that much more wort. Beersmith, or any one of the online software can help if you don't want to do the math manually (although there is generally a learning curve to those softwares).
A beer that big, and by all appearances it's a type of barleywine, is normally pretty sweet and malty, relatively speaking. I'd let some others chime in before committing to a recipe. Just to get a consensus.