i think the first thing to do is start making a few guesses about the number of players and the average number of rebuys. if you have some local knowledge of the casino you might be able to make some decent guesses at this

this will give you some indication of the average stack at any point in time. 

usually from that you can work out how long the tourney will last, because once you get down to 20bb for the entire tourney for instance, it will be the last level almost guaranteed. 

so, for the sake of argument, say there is 50 players, and they each make the initial buyin, and two rebuys and a single addon. so they pay €200

this would make a prize pool of 10k. if we rake this at 15%, could be as high as 20-25% for a low stakes tourney like this depending onwhere you are playing, but this would give 8500 prize pool and 7 tickets, and 800 for 8th. 

so now, with two rebuys and the addon we get a 10k total stack, so we have 500k in chips to work with. 

so, after 4 hours and 20 minutes, with the amount of runners and big blinds mentioned, there is still 125bb in play in the tournament, which doesnt sound like a bad structure. 

if there was this many people playing, i think it sounds well worth a shot. 

if however, there was only 10 runners for instance, you would get a prize pool of 1700 and it is almost a winner take all, even assuming everyone rebuys twice and adds on which is not always guaranteed. 

you would then only have 100k in chips, which means the average stack is going to be shallower. 

sorry if this is tldr, and i know i have a preference for super satellites instead of the more winner take all style MTTs, but i hope i have at least given you something to think about