Are you 'flying' your figure 8s or hovering?

Hovering is easier at lower heights. Anything up to 15 ft or so is pretty straightforward. Hovering at 30 ft upwards gets more and more difficult. Normal forward flight at 15 ft is VERY low. 30 ft would be OK I guess. This is obviously dependant on speed (the beauty of helicopters).

Obviously the first loop attempts are from fast forward flight (i.e not hovering flips). You therefore need to be comfortable at flying at height. I can not be sure of exact heights but I am guessing that my first loop attempt was at about 200 ft. This may be a long way out but what I am trying to say is that it was high. It is just at the point where I could just make out the orientation. From 50 ft you will not have much time if it all goes wrong.

It does get harder to fly the higher you go but it is worth perservering with. It sounds like your field is big enough.