We do a couple of churches,the first thing you need to do is check your public liability covers churches,some do,some dont, the modern church windows are quite easy to do unlike the old leaded,the first time i did one,i used tfr on the windows first because they had not been done for ages. we normally charge inbetween £50-£75 for these modern churches. it should not take you any longer than 1 hour to do it. hope this is some help to you.
Malcolm