richtea
The two line tank seems to be an american thing, convert it to three lines then you will not have to detach the feed line to fill the tank, one thing most people seem to have a problem with is the tank position as previously stated, it needs to be moved down to facilitate an inverted engine, I'm sure you know how.
A single aireron servo? don't know about this one, it must be an older kit as you say, suggest you convert it to two servo's, should be quite easy.
Mike