as a frequent leecher i would not pay more zeny than GJ on the ratio of 1000:1 for a champ. basically 1m and 1k gj is is what i would go for. 1m plus 700gj is a rip off for me. 1m and 1.5kgj is a deal for me, and probably good for a starting leecher as far as expectations go.
i would say to NOT focus on time spent as much as gj spent. if you are focused on an hour and dont use all GJ but say you do... shame on you... if you just go until the GJ train is empty, then people will flock.
dont be a jerk, its how bad karma strikes
all in all, good luck!! i hope you become a successful leecher!