Your normally ok leaving the fuel in for say a month between races. Some people say drain the fuel but i don't and to be honest its never made any difference (2/ Rotax Max) its still quicker than Super 1 spec engines.
As for the tank....hmmm, tricky, it sounds like its positioned right. Ours is attached between the two chassis rails leading up the the steering column by one bolt and is a "quick release" type. However it does take some banging and shifting etc to get the tank out and it can also only be pulled out to the right as we can't get it over the brake reservoir otherwise.
Hope that helps
