Just go for it! I got a couple of ponies back from the breaker and he didnt lunge them, and before I got on to ride I lunged them with a saddle and they were fine... sure a bit confused at first but they picked it up quick smart
although I did have a round yard to work with... the smaller the space you begin with I think is best because they kinda see 'well theres no were to go but around'...
Just make sure you no what ur doing to lol or the poor pony wont have a chance... while standing in the middle, make sure you are always behind the horse or they will stop if you end up in front of them... it gets dizzy but oh well haha!
Let us no how you go good luck