My cousin killed his bull this year with a 60lb bowtech realm, 380ish grain black eagle rampage with rage trypan, pass through, blood everywhere, broken ribs, lights out! The expandable looked brand new still...the new rage trypan is no joke...this makes four elk in the last three years our group has killed with rage broadheads all with 60lb bows and sub 400gr arrows. This is not meant to trash the heavy arrow/fixed blade crowd, but I wouldn't get hung up on trying to get over a certain number weight wise. I find its more important to build an arrow that makes sense for your setup, correctly spined, proper length, straight as you can afford, with decent FOC, that goes where you ask it to go! Slap a quality broadhead on (we use rage broadheads because they just flat work...) and hit the woods!
We shoot black eagle rampages same setup at deer and elk...they are a .204 shaft and we buy the .001" with 56gr stainless outserts. You have to make sure to dry fit/spin test the outserts prior to gluing them in to make sure there is no wobble in the outsert. These are the most affordable, straightest arrows you can get. They are also nice because you can shoot a regular old X nock and not worry about nock bushings robbing your FOC. The next closest thing is the Victory RIP .204 which are much more expensive. I don't have any experience with the victory shafts but hear a lot of good things.
Like TheHunt mentioned, do what you can to lighten up the arse end of the arrow. Three fletchings, no nock bushings, no lighted nocks, no wraps, will help you build in more FOC.