Hi Tony,
The first coat(s) of Klear are vital because
decals only adher well to glossy surfaces-matt paint is like the surface of the moon to a decal! In this case I left the
decals for about 48 hours to really dry out thoroughly, as I've has similar problems before. I found that extra time was well spent coz they had stuck down very well. The light sanding was done just to take off the barest minimum of the top layer of the decal & I did it all over it, not just at the edges.
If you need to lay a decal over bumps & protrusions, I would recommend Microsol products-one you apply to the models surface prior to putting the decal on & the other you apply over the decal to help it snuggle down.
Revell also make a 'decal-softener' which I've used & this does just what it says, it softens the decal to make it easier to fit it over rivets, hatches etc. On the T-34 turret there are a couple of vision-slits & this stuff allowed me to mould the
decals over them with no problems. Sometimes you'll need to keep adding a little more until the decal is soft enough.
Of course, it's handy to have spares because there's no guarantee that it works first time or even all the time!
Patrick