Its really easy. The micro arrows are .166 in inside diameter. The outside dimension will vary with the spine, because the wall thickness will vary,rendering the outside a little different diameter, larger for the heavier spines. But basically the arrows will be about 1/4" in OD. They must use an outsert system to accommodate the 8/32" thread on all standard components, and the basic 5/16 OD of broadheads. These arrows must be stepped up to fit the components that fit the industry standard arrow that is .245ID and about .293 to .300 outside...or 5/16". So...this is where the "outsert" comes in. You can use the manufacturers outsert, and sometimes they offer more than one. And there are some companies that make aftermarket outsert systems, you just have to be careful to make sure you are getting the right size to fit the outside diameter to fit your particular arrow.
The exception to this is the Easton Deep six insert they offer which is a smaller thread, and does require a different broadhead, if you want to research that fine, but to minimize the confusion leave it out for now.
These outserts are the biggest source of complaints. They basically work fine, but occasionally if you strike something hard especially at an angle, they can bend. To me its infrequent enough to discount, but it's a big deal to some. So, they will either not use them, or seek out a full stainless steel outsert, or just a system that they is more durable than possibly the one which comes with the arrow. AND...sometimes guys want to customize the weight, so they will use an aftermarket which is heavier than possibly the one that came with the arrow. This can all get really expensive.
If you want to try some to get your feet wet. I would recommend just buying a couple and shoot them for a while to see what you think. Use the standard components that come with it to save on cost. If you are one of the fortunate souls that has a pro shop near you that stocks and builds micros, just have them put together a couple . If not, Lancaster's will sell individual arrows of some if not most arrow shafts. I would say buy a couple of the cheaper ones to see what its all about. Typically like the .005 to .006 straightness. Gold tip's micro is the Kinetic" Pierce". They also make a Kinetic which is .204 ID, the "Pierce" designates the .166 . The Pierce Platinum is the straighter one, the standard Kinetic Pierce is .006. It cost about 11 bucks for a shaft,comes with the nock and outsert system, which theirs is an insert with a collar that slides over it, two piece. But these are shafts and need fletched, so if you need to buy fletched arrows you will have to buy 6 minimum I think. That makes your experiment more of an investment. If you can fletch so much the better, having them cut is cheap, and they will install components for a little, or ship them loose. You tell them to cut them to a specific length and then you just have to fletch and install the components. Or buy 6 complete arrows....and just start shooting.
Are they worth it....well. For long range especially in wind, some, especially if built right. For penetration, well....maybe a little. And to me its not about the shaft presents less friction because of its diameter, its a physics thing, where the energy and mass are focused more inline directly behind the point of the head. Is it real? I think so...is it a big factor? Well.....if you build a really good weighted and balanced standard arrow, and a crappy micro...I would rather have the standard well built. But a really well built and weighted micro has some merit. But Its not the type of thing where you should be bragging my arrow is better than your fat old arrow.
Anybody, and I mean anybody can make an argument not to use them and it would have validity. But I am one of those guys who will try most anything. And I have every size hunting arrow, and don't really hate or love any of them more than another.It's my harem. I have multiple bows, and I will set one up with micros and one with .204 ID's and one with Easton H and maybe one with standard diameter. Use one in the morning and one in the afternoon. And yes....I am a nut.... a harmless one....but a nut. Not a " hold my beer" type so much, just a " so what will this do" type.
Victory offers the "VAP"
Gold tip the "Kinetic Pierce"
Easton the 4MM Axis long range
Black Eagle the "Deep Impact" and the "X impact"
And their are many more in the Easton line in the target style, and more manufacturers and ....this is just a few
You need to figure out what weight you want to shoot, and about what FOC. This can have some bearing on the one you select, some are heavier than others, in the same spine. And some have heavier outserts than others.
So if you say I want a 500 grain arrow with about 14 percent FOC....then you can pick a shaft and components to make that happen, or at least get close.
If I just wanted to drop some coin, and was a serious big game hunter. I would give some serious consideration to the Victory VAP SS. That has a stainless steel weave in the arrow, it will be tough as all get out, and has a weight that will render a mass, that if the concentrated energy thing has some merit, it should up the game a little, but expensive.
I do not try to talk anyone over to any particular size, I just try to tell you about whatever you inquire about. I do think for most people who really have no interest in anything but the most practical, stay with standard. But if you like to play around with stuff I think its fun . The .204 size is good too. But I like my micro .166 too.
You have to bury your nose in each manufacturers info to begin to see what they have and what they have to offer.