Some mobile therapists find the smaller pots of wax ( 400g) easier to work with for mobile work, but it all comes down to how much waxing you will be doing each day etc...
There are loads of waxes that vary in price and quality and maybe get some samples of the wax and try them out for yourself.
Also have a search through some of older threads as there has been many threads about mobile waxing with some great tips for storage, transport and heating them up when you get to your clients home and you may find these helpful.
Good Luck
Jack