RE: 3 or 4 channel trainer?
hammonsr,
Here is my opinion on your response.
Teaching yourself to fly can be a time consuming,costly,dangerous and frustrating way to enter this hobby.....
Could you do it??? Most likely!! Should you do it?? ONLY YOU can answer it!!!!!!!!!
You state you want to progress towards Larger Glow powered models... Then I would start with a glow powered trainer as far as which brand/model I don't think it matters much when you are being taught by an instructor.
If finding an instructor will present a challenge A simulator might be a good way to start.
If you can learn before your job takes you "away" thats the route I would go. BTW if you're going overseas your radio gear may not be legal??? Different countries reseve different bands for RC use... You might want to check before you buy anything