Recently ordered the 5D tactical jig and bit set. I will be using a Dewalt DWP611. Am I assuming correctly the the end mill it uses replaces the collet system and screws directly to the router?
Also is drilling the FCG hole with the 5/32 bit perfectly fine or is it better to drill undersize and then ream? I think I've read somewhere that the actual FCG hole is actually a little smaller than 5/32 (0.15625). Also with the jig is using the router ok for the FCG hole or would it be much better to use my drill press, a Nova Viking 83700, and use the jig as a guide. With the jig do I have to still worry about the bit wondering and need to use a spot drill bit first? I've been thinking of getting a precision collet for my drill press, will probably pick up a Llambrich 4LHG5 keyless precision chuck at some point in the future if not for this. I do still need to get a Mitutoyo dial indicator so I can double check the run out of the chuck my drill press came with.
And speeds. It sounds like for drilling aluminum I should want somewhere in the 2-300 rpm speed, which my drill press can go down that low. And only need WD40 out of the can as a lubricant? Is WD40 even actually a lubricant I thought it was actually technically a water displacer?
For milling I'm finding it difficult to find the correct RPM. It seems like maybe either 13 or 15k? The Dewalt has a variable speed of about 16k up to about 27k, so I'm assuming I should set it to the lowest speed? Since I am using the Dewalt as a mill I'm guessing I should just spray a lot of the WD40 between each pass since I have no way to really give it a constant stream of spray.

I don't really have much actual machining hands on knowledge, but I do watch a lot of This Old Tony and every single Clickspring video that is put out. :) And I have used my router for some woodworking projects. I understand what is going on pretty well I think just not much actual real experience.

Thanks! That review link is pretty helpful and answered a few things.

Go slow and be overly cautious.  Take the first one as a learning experience.  $40-60 for a lower is not the end of the world.

For the fcg i found that 5/32 is fine but it is better to have a good quality short jobber length drill and keep it as close to the collet as possible.  Avoid using a chuck.  You dont want it wandering at all.

For the safety i had all kind of issues with the hole being accurate which improved a lot by using an endmill vs a bit.  The bits for 3/8 are just too long and pull the work because of the sharp angle.  An Endmill which can plunge cut gives me a better result.

Use a drill press to drill all the FCG holes, including the safety.  This will minimize bushing wear and ensure the holes are perpendicular

If your safety detent doesn't seat all the way, clear the channel out with a hand twisted 1/8" bit - Aluminum gets in there. Other than that, I had zero problems with 5D stuff on a DWP611 - used ample actual cutting fluid, and hand drilled the side holes with no problem.

This

No issue with my first gen 5D, finished many lowers.

OP we need pics of your lower.

+1
Or purchase a reamer, drill undersize and ream to proper dimensions.

Plunging an end mill, especially into an anodized surface will wallow out the hole.  If you feel you must use a milling cutter, use a 90 degree center drill cutter.

Use a starter drill, drill undersize and ream.

Best practice IME.

Not familiar with any of the jigs being used but if they have a drill bushing it is advisable in my opinion to use a drill that matches the bushing ID. A smaller drill in a larger bushing will end up off center, that is the function of a drill bushing, to keep it centered. I do it on the drill press and have a homemade but precision drill bushing plate that locates off of the takedown holes and I drill the 5/32 holes all the way through both sides in one setup. You must have a quality drill that is sharp and go gently as it enters the second side but the bushing does its job and I have done many with great success. The reason I go through both sides at once rather than entering from both sides separately is because, due to dimensional tolerance stack ups, the two sides will not be precisely aligned. I do the 3/8 selector hole with the same bushing plate but I do that before machining the pocket. A drill works best when it is going through a solid mass and the two flutes are equally loaded but the pocket has steps in it that will cause the drill to snag and jump as it hits these steps. (The 5/32 holes pass through flat surfaces) My process comes from 40 years of machine shop and engineering experience but your mileage may vary.

Mcmaster carr sells some precision stainless tubing with an outside diameter the size of the hole in the bushing and an inside diameter that match's a reduced drill bit size. I used it to cut some sleeves for the bushings on my jig when drilling mine then pulled the piece of sleeving out and reamed the reduce hole to size.  Found it best to stop the reamer as soon as it went through the first hole then drop it to the second hole to start the machine back up and ream it in order to stop any runout or wobble on the reamer from oversizing the first reamed hole.
I made an alignment block with the hammer trigger holes that drops into the trigger pocket and clamps to the top of the jig to keep the bit from walking out of alignment when I drill the second hole.