Budget Travel - (Most of the way) RTW on LCC's - carry on luggage questions.....

After spending so many months preparing for my move across the world from the sunny Gold Coast of Australia to the crazy cold of Montreal, I have decided to join the forum and become an active participant. Hopefully all the dedicated flyers out there can help me with an issue I have come across with my tickets......

My fiancee and I are flying from the Gold Coast to Montreal the following (long) way at the end of March....

Coolangatta to KL - Air Asia X
KL to Bangkok - Air Asia
Bangkok to KL - Air Asia (this is just a little side holiday on the way there)
KL to London Stanstead - Air Asia X
London Gatwick to Basel Mulhouse - Easyjet
Paris to Montreal - Air Transat

All connections missing are overland and not an issue. We are going all over the place to visit friends on the way back.

Now to my question :D

I have looked at the carry-on luggage requirements for these airlines and based on their websites I have the following restrictions:

Air Asia - 56 x 36 x 23cms - Max weight 7kgs
Easyjet - 55 x 40 x 20cms - Max weight "reasonable':confused:
Air Transat - 51 x 40 x 23cms - Max weight 10kgs

I am not so fussed with the weight side of things after all they are all LCC's so any chance to slug you for that extra 300grams they will.

What I want to know is what sort of chance can I have taking a bag that will fit these measurements at all the airports I am flying from? I remember reading somewhere that airlines are ok as long as the total measurements of the bag fits into the total of the restrictions (ie. Air Asia and Easyjet is 115cms, AT 114cms). Or do I find the near impossible minimum measurement of 51 x 36 x 20cms?

As I am moving to Canada and not just holidaying, the total space and weight I can carry needs to be as much as possible (not to mention the girls insatible shopping desire when in Bangkok!)

Any help or personal experiences would be great.

Cheers,