Just a few tips from a professional finisher....
then a question or two.
First, I wouldn't suggest using a brush of any kind as you are not going to achieve an invisible screen "guarranteed". You will always have compromises. I am going to experiment with the aluminium paint to see how it works for me. I will also talk to my supplier to see what may be available in commercial lines that may not be readily available on the retail shelf. If I come up with something superior I will share it with you.
Second, I notice that you are tryng to create a full torus screen, in other words bending it both horizontally and vertically. Without being able to stretch the material there is no way to create a screen that will not show warpage. In one of the puctures you can see the shadow created by the uneven shape. This will show up in the picture.
I am interested in building a torus screen for myself and my daughter but I will not attempt to bend the screen in two directions. You would need either a giant vacuam former or shape one out of a mouldable material, very dificult indeed. I would take the verticle pipes off and replace them with straight ones.
Third, the material you use can help to make the finishing much easier. If you intend to make a flat screen you can either make a screen from ridgid material or even make one from fabric and then paint it. Yes you can paint fabric and make it look very good. Start with the best quality blackout material as you can find. Build your screen and then spray it just as you would a ridgid material. I have even sprayed interior padded vynil in a show car. I added a flex agent to the paint and you would never even know it had been painted. It looked and felt like factory. It is flexible and soft but very durable. I would also suggest to purchase an inexpensive HVLP gun to do the spraying, that way you can set the gun to create a nice wide spray pattern and regulate the fluid fow and success will be much easier to attain.
For both torus and flat rigid screen, I would highly recommend using MDF. This is a rigid board that is very flat and can be painted to look like glass. For a torus, I would build a basic frame then screw the MDF into it from the front along the edges starting in the middle. I would use 3/8 or 1/4 for a torus but if it is flat you can use 3/4 inch and you don't even have to build a frame. Just remember to paint the back side too or it will warp. For those of you who have larger screens you can buy MDF in over size sheets. For about 60.00 canadian you can buy a 5 by 9 foot sheet. In some areas you can even buy 10 foot long sheets. These will have to be ordered though. I suggest that you prime the MDF with something like Kilz, then sand it to a silky smooth finish with 320 grit paper. Now you are ready for your white base coat. With the right material and practise you can spray a screen that will look very nice and be almost invisible. remember to thin your paint to the point that when you raise the stir stick out of the paint, you see the liquid dropping off the stick nearly in rapid drops and not running like honey. This will ensure that the finish will not have orange peel and will settle nice and flat.
I hope some of this info. will help
I will keep you all posted as I begin to build my screens with pics and proceedure.