I have a tip...
Do not wear lace knickers for a spray tan!
I wore lace knickers for my first spray tan and had a very fetching flowery pattern across my bum where the tan had reached some areas and not others.
DP found it highly amusing and I was just grateful that I hadn't had the tan in preparation for a beach holiday!
On a separate note, make sure you don't wear anything with tight elastic afterwards as it will rub the tan off. Also, make sure you have an umbrella with you, because if you get rain drops on you then it leaves lovely reverse dalmatian spots.
I have learnt this the hard way!
I have had mine using Sienna X and I asked for a light hint of colour. I am fairly fair skinned and have medium brown hair, and I tend to have one for special occasions. I've always been complimented on how healthy and glowing I look, rather than an obvious tan ifyswim.
I think asking for subtle is the trick to looking good with a fake tan, rather than orange!
But it does seem to depend on the beautician you go to. The lady who does mine has very similar colouring to me and only ever has a light application herself. I think would be a bit apprehensive if she was bright orange herself though!