I have done 6 AG style guitars, five 6 String and a bass and I am about to start another and put some filtertrons in it as it was all I could get at the time. Not knowing you skill base I will surmise that you have enough skills to perform what I am about to convey.

I have used in the past blank pickguards that I have got from Amazon that only have the outside with no pickup cut-outs or any other holes so it doesn't matter what pickups I use. You can position the pickguard closer to the neck by trimming off the front as long as it doesn't interfere with the guitar bevels. If you use a standard full face SG pickguard then you can only adjust the bevels so the pickguard doesn't overlap the bevels so if you haven't done any work to the bevels it does allow you purchase a pickguard and then make the bevels to suit.

If the pickguard you purchase has the screw holes around the perimeter that are used to hold it in place then you can't modify the outside to suit the guitar bevels but I have in the past been able to purchase a pickguard with no holes but unfortunately I haven't seen any for a while.

I normally make the AG bevels quite large, closer to proper SG dimensions as I found the information online and the larger ones look much better than what is on the kit. To make a pickguard is easy as I have a few that I have had to make as most guitars I buy are blank so I can make it however I want. This is how I have made my own, sometimes with a router to cut out the neck pocket but I have done most with hand tools and they are just as good.

I use some thin cardboard which is about 2 or 3 times the thickness of a single piece of paper. Some places sell it and you use it as display backing. I roughly cut it out so it doesn't overhang the outside but I use a straight side pushed against the neck as a datum. I place a pencil line on each side of the neck so as to keep it centred and I place a centre line that matches up with the guitars centre. If I want the pickguard to go on each side of the neck then I just hang it over the neck cut-out and use a razor blade to trim around the inside of the cut-out. I use the guitar bevel dimensions of 20mm in from the outside and 10mm down from the guitars face but seeing as I am making it I can make it what ever I want and I like the look of consistent sized bevels and I run them around the outside as far as I can. I do me and I know what I like.

Once I have placed the cardboard in place I hold it down with some masking tape, I use the green painters tape as it is easy to remove and doesn't leave glue on the guitar. I have already put the bevels on my guitar so I just go about 3-5mm inside the bevels. I then glue the cardboard to the material blank and use a saw to cut around the outside. I have used a hacksaw blade holding it in my hand, I have used a coping saw with a fine toothed blade and a scroll saw. How ever you cut it out doesn't matter as you will be cleaning it up. I use a fine toothed file to file down to the line or I have filed it so it has some left to clean up with a razor blade by scraping so as not to leave any rough edges. It does take some practice but it is easy. To put the 45 on I was going to use a router but I didn't have a 45 cutter and I dont use mdf as it all adds up in the cost of the guitar. I made a razor blade holder that holds the blade at 45 degrees using a piece of pine and cut a 45 degree notch in it and screw a razor blade at 45 and scrape the outside until it is bevelled where it should be 45. I find it easy to make pickguards and as long as you don't over complicate things its easy.

My latest AG kit I picked up as a second as it had a chip near the neck. When I got it home the chip isn't really worth worrying about as I can fill it with some filler but I am not really all that worried. This is the guitar I am going to put the Filtertrons in and I am going to put in a through body bridge as that is what I like. Anything is possible.