Zelda Hyrule Shield - fibre glassing

My Hyrule shield is nice and fibre glassed. It took some time because I did it in 2 parts. The first was to fibre glass the shield base so that it was nice and stiff. That way, I can put the details on without having to worry about the details bending that base.

Here it is, all nicely fibre glassed. There is something that I kind of regret and I'm wondering how to improve. I applied the fibre glass resin on the underside of the details so that it would hold it's shape better. The problem came about after I applied it, the piece was still bendy and I need it to harden into the right position. I applied some resin to the base and loosely stuck it down. I really needed a way to stick it down much better, maybe with some masking tape, but right now (I don't think you can see in the picture) there are gaps between the detail and the base. I think a few more layers of resin could sort that out, or even when I apply the P38, it'll fill in the gaps automatically.

I modified the centre triforce part slightly. Looking at a number of pictures, the top of that piece should go into the top part of the shield, so I cut a bit off before sticking it down. I also cut a bit more off around the other sides so that more of it will stick closer to the base.

One major thing I have learnt from the Iron Man helmet is that I need to apply the P38 in THIN layers. I still need to be able to see where the edges are and slowly add more to model it. The Iron Man helmet is now in the process of being drawn on, sanded down, and then realising that I misses and having to add more p38 on to create a new detail feature. I'm wondering should I start over and assume the first test piece was a failure...... or work in progress...... forever.

Probably one more layer of resin before I continue onto the P38, however, a question has popped up: why do I need to cover the whole thing in P38? Can I just use it like filler and have the outside mostly resin? The details are all there, it just needs a little touching up and slight altering to make things a little smoother. I only have a few reference sites to look to and it seems like everyone covers their models in bondo. I'd better go and check more out to see if I can take this short cut.