Lots of good advice here. I doubt I'll ever build a model that satisfies me. I'm learning to accept that. Make yourself happy, Mickael, don't worry about some arbitrary standard of perfection. There will always be something wrong when you're done. It's no big deal. Do like me and display them with the best side out.
I've certainly learned some things from this discussion. Great stuff!
I don't need any convincing on Tamiya TS lacquers. Cost and availability are the issue. After shipping, I've got about $8/can, if I only order 1 or 2. It drops to about $7.25 if I order several. But anything I've painted with them has come out pretty good for my skill level.
As for the acrylics, it's just tempting to put in the time to try to master them but I'm starting to feel like a dog chasing it's tail. The Paasche H can be had for about $50-60. Maybe I'll find a deal and can try one some time. In the meantime, I build mostly race cars which have large amounts of blacks and metal colors (aluminum, steel, etc). The acrylics will work for that.