Leave everything you know about tuning a compound at the door when you start tuning your longbow. While they are both bows and both accelerate an arrow, when it comes to tuning they are different beasts.
There's lots of way to achieve a good tune, my favorite is bare shaft tuning. I pretty much follow the procedure as outlined by O.L. Adcock several years ago which can be found here these days...
acsbows.com/bareshaftplaning The basic procedure is to let the way your bare shafts group compared to your fletched shafts tell you where to have your nock point (and point weight or arrow spine/length). It's a very easy process that becomes even simpler after you get the hang of it and is very well described in the link. The easiest way is to have a selection of different weight field points and do as the link describes. The idea of starting with a high nock point when you do your tuning is a good one, makes things simpler. Start close, if your arrows setup is off more than a little a bare shaft can plane enough to miss your target (depends on the size or your target...lol). Move back in increments as your tuning progresses. When you get your bare shafts and fletched grouping together at 25-30 yards you have everything pretty close to perfect in my opinion but theoretically you could keep moving back even further. At that point I've never had to change a thing to shoot broadheads, just make sure they are the same weight as your field points and obviously shoot them for peace of mind.
You don't say if you are shooting three under or split finger, but many three under shooters end up with a significantly higher nock point than 0.25" above level. I shoot split and mine is higher than that too at 0.625" above a line perpendicular to the shelf.
If you aren't doing it now, I would recommend using two nock points, one above your arrow and one below, especially if you are shooting three under (I use two even shooting split). No disadvantages and it can eliminate a source of potential trouble. Tied-in nock points are easier on gloves and tabs.
I haven't shot an arrow through paper in years, but I don't think paper tuning at 10 yards is really telling you anything, the fletching is in control at that point.