Salut Denis,

Pablo is absolutely right about the weight, because after playing and moving around somebody for more than 15 minutes you will feel the weight of your didge in your arms.
Apart from the weight I consider the sound the most important, since the idea of playing 'on' someone is to make his body 'vibrate'. That's the reason why didges made out of PVC or carton don't work for sound massage, their sound doesn't really vibrate that strongly.

Interestingly enough wood-didgeridoos with a good sound often have the same lenght-weight ratio = their wood is not to thick so they are not to heavy for their lenght !?
I for instance prefer to use my D' didge, since it is like that. My C' didge has a nice sound, but doesn't vibrate (not sound) that much, whereas my B' didge vibrates a lot (can't read a didgital clock while playing it!), but it is 1.80 long and very heavy.

There is also the aspect of the note and or tonality:
B' and C' are 'low' tones and might create a feeling of heavyness. E' and F' are really 'high' and might annoy the person receiving. I found D' being the best choice since it resonates strongly in the lower body, but still has an uplifting feeling to it.

Anyway, if you do own a didge already, try it out on someone who's jugment you would trust.
If you think about getting a didge, I would trust the Didgshop guys, since they really know why they consider a didge god for concert or healing or anything else. If you hesitate between let's say a concert and a healing didge, send them a mail and ask them for their reasons to classify them like that.

For the rest, maybe you want to meditate your real needs as a player, what would you use it for ...( l'enjeu mon vieux, toujours verifier l'enjeu qu'on a !?).

Namasté (Bon Voyage)