In-ear monitors: ambient noise, custom molds and limiters

[Sevrin]

Hi folks,

I plan on switching from headphones to in-ear monitors (IEM's), mainly for protecting my ears, while maintaining sound quality. After some on-line research, it appears that IEM's have some real pros, though there are some cons, and these can be summarised by: 

Pros

• Superior sound isolation allows you to keep the volume of your IEM's at a very low and therefore safe level. 
• Sound quality is not compromised by safety (as with headphones with musicians ear plugs for example), and in fact, IEM's will often sound better than many headphones 
• Portability, less cumbersome than headphones

Cons

• IEM's used while DJing, require the DJ to mix via earphones, and not with monitor speakers. The one-can-on and one-can-off ear method of mixing doesn't apply here. Exposing a naked ear to loudness defeats the purpose of IEM's. Many Dj's just don't enjoy this style of mixing so this could be seen as a con by some. 
• The downside to amazing sound isolation is feeling disconnected to the audience. DJ's can feel like they're in their own little world separate to punters. 
• Acoustic shock by (generally accidental) high volume would be worse with IEM's than regular cans.  

I'm really keen to explore solutions to audience disconnection and the potential for acoustic shock. I have some questions: 

1. Custom molds are known to increase isolation and comfort, but will this further increase audience separation?
2. Has anyone had experience with IEM's with db filters to allow some ambient sound in and therefore reduce the 'bubble effect' when performing?
3. Has anyone had experience with limiters that block sound if it reaches dangerous db's? Is this a reasonable solution to avoiding accidental acoustic shock? 

Look forward to feedback re: the above IEM issues when Djing. Thanks in advance!