Well I would say you need to figure out if your field is dominated by sprinters then try to rally another guy or two to go on a flyer with you. I think this should be easier in the 45+ class since you will most likley see the same guys week in and week out to figure out the strengths and weakness of all.
do you mean 4.2 for 20 minute power or hour power? 4.2 for an hour is strong.