Hi Ray,
I think you'll find the Aviattic decals really make a difference to the finish of a model.
The things to remember with these decals is they are not like standard decals and care is needed to ensure the surface is prepared correctly before applying them.
The decals themselves come as either 'cookie cut' for the relevant aircraft or as full sheets. With full sheets the decal shapes will need to be cut from the sheet to fit the particular model surface. This might seem a daunting task, but create templates from paper first and once you are happy with the fit, use these to cut out the decal from the sheet.
Before you apply the decal you'll need to apply a base colour to the model. This colour depends on the finish you require, so test on a piece of plastic card fist, especially if you are going to pre-shade the surface as well. Normally the colour will be light, such as white or cream.
Once dry make sure the painted surface is really smooth and free from imperfections, such as trapped dust, scratches etc. If necessary polish the surface with a polish compound, or sand with a very fine grade paper or sanding stick. Finally clean the surface thoroughly.
The decal material is surprisingly strong and will stretch slightly if required. Don't leave the decal soaking for very long or you may 'wash' off the backing too much.
Apply the decal in the normal manner but make sure all air is removed from under the decal. Unlike normal decals, setting solutions such as Micro-Set and Micro-Sol don't seem able to penetrate through the decal material, so are ineffective for bedding down the decals. Consequently any air trapped under the decals, once dry, will cause silvering, which is difficult to eradicate.
If you are unsure, practice first - they need a different approach to normal decals, but are worth it, as the finished effect they create is very realistic.
I build in 1:32 scale and my last two models have Aviattic decals (Fokker E.V and the Sopwith Pup) and both required cutting from decal sheets. Both have build logs in PDF format on my model site - you can download or refer to them if needed.
http://igavh2.xara.hostingMike