Hi Joe,
I now have a series III ASP .52 2 stroke in my Tucano. It is identical to the Magnum.52. The cowl fitted with little mangling. I used a dremel tool with a router bit to cut a hole between the air intake opening under the prop driver opening, to allow room for the carby, as the carb did prevent the cowl from fitting correctly.

I also dremeled a small concave opening just under the carby hole to allow better airflow into the carby.

To strengthen this latter section (as the cowl was now a lot thinner at this point) I epoxied a small piece of brass fuel tank tubing across on the inside. So far it has stood up well.

Naturally you will have to cut out a piece for the nose wheel and drill a hole the carby needle and idle speed screw. No big deal. Just ensure that the piece cut for the nose wheel is big enough to allow for sufficient hot air exit.

I have attached a couple of photos of the nose so you can see what I did.

As for the muffler, you can chose between an inverted type muffler such as the unit that Slimline makes to suit the OS .40-.46. SF (Slimline part no 3208, pic below. You will also have to drill and tap it for a pressure fitting and cut the twin pipes to get the correct length for your model if you use this one) or the stock one supplied with your engine.

I used the stock muffler and found that I also had to use a Dubro Muffler Extension ( Dubro part no 638, pic below) because the muffler made contact with the cowl side. The extension stopped this.

I also fitted a remote filling valve.

One other mod. My model had self tapping wood screws to secure the nose wheel leg mounting block. I junked them, as well as the supplied wheels which were "square."
In place to secure the aforementioned nose wheel block, I used 2 pairs of machine screws and matching blind nuts.

As for the wheels, I used 2.5 inch Dubro's.

Prop is an 11 x 7 RAM (from the U.K.) and the spinner is a Tru Turn.