I am curious about how you go about determining the proper arrow weight. Is 5gr/lb of draw weight correct?

That is the IBO's min arrow weight.

I prefer to test each of my bows to see what arrow weight the bow is most efficient with.
My current Black Knight 60lb 28" draw is more efficient with a 400gr arrow than it is with a 300gr arrow

So is the 5gr/lb of draw weight a good starting point? How long do you spend finding the right arow combination? It seems this could be an all day affair finding the right arrow spine, tip weight, etc.

i think personally 6 gpi would be a good starting point, speed is fine but accuracy kills i am currently shooting a 5 gpi (350 grains) arrow for 3d and a 500 grain arrow for hunting both shoot really well in my bow because they are spined correctly, but the heavier on drops off a lot more, both would work for deer hunting though. it is all in your preference.

It took me a couple weeks to find the perfect setup. Yours probably won't take that long I'm sure. I got way too technical. Accuracy is way more important than speed. (Read the signature).

An all day affair, you ask? I've been playing around with this stuff for over 30 years. That's half the fun of shooting archery in the first place. Learning. Recently I got a new bow. In two days I had 7 different drop-away rests on the thing to see what I might want on it. I don't consider it wasted time. I learned a lot in the process.

Arrow weight is not the criteria you should use when picking an arrow. It is only one. Proper spine is the most important. There are a multitude of different weight arrows, both carbon and aluminum from a dozen manufacturers. You can get a properly spined arrow that is light so you have more speed. You can also get one that is heavier to get more momentum. So long as you stay above you bow manufacturer"s minimum weight per pound of draw you should be just fine. This is usually 5 or 6 gr/lb.

A decent place to check out arrow specs is www.bowjackson.com. Just put in your bow specs and arrow length needed and it shows what arrows are recommended.

Seven different rests?! Holy cow!! Did your shop "loan" them to you?!
OK, here is a loaded Q. Aluminium or Carbon? Is it a matter of preferance or peformance?

I use a heavey enough arrow to slow my bow down into the 260 feet per second range. with the bow I'm using, that arrow weight came out to be 411 grains, complete arrow. so that's what I use. I find it easier to tune at the 262 feet per second speed, the bow is quiet with that arrow weight and speed. I don't have any tajectory issues with that speed. Plus it worked all last year

So a good shop should/would let you try out different arrow/tip/fletch combinations or do you just guess and hope to hit a bullseye?

I'm sure some shops would let you do that, but mine doesn't. I just buy one arrow and the acessories for that one arrow. I shoot it and if I like it I get more.