Picnic Tap dilema

Until I can get the parts to convert my mini fridge to a kegerator, I am just using a picnic tap. I am using 3 gallon kegs and my serving line is about 7 feet long (I read a longer line reduces foaming). I have noticed that after pouring, the bubbles will rise to the highest point in the line and get stuck in a lot of places. If there are bubbles trapped in the line, will this cause foaming when I go to pour? I kegged this last night and set it at 30psi for about 20 hours at 38*. When I pushed it out at 10psi I got quite a bit of foam. The level of carbonation seems to be right, but I am still getting a fair amount of foam. Any suggestions? I have a 4 foot serving line aswell. Would hooking that up make a difference? Thanks again everyone. Are 3 gallon kegs more finicky when it comes to this type of stuff?

I had a smiliar problem but had only 4 ft of hose on my picnic.
After it was carbed I set serving pressure to 8-10psi and it also helped to hold the tap as high as I could when i poured basically eye level.

yeah, the bubbles will cause foaming for the first split second, but then should poor nice and clean. When i used to run picnic taps i usually just poured the first bit of foam into my glass, drank it, then poured my pint.

Foaming from picnic taps often occurs if you are not opening the tap all the way. When using picnic taps I make sure to set my psi to a serving pressure rather than a carbing pressure, hold the tap as high as I can, and open it all the way even if I get some initial foam.

i can't give you an answer myself, but a great place to read about this is the draft beer quality manual. if i remember correctly, its like a 20 pg pdf and is pretty helpful in determining line length and temperature to serve kegged beer.