Alright, well the fee doesn't seem to be a problem. Would people be satisfied with it being advertised as "Not for profit pool, all mining is at miners risk." Just like a car park, all care, no responsibility blah blah.
From what I understood, you do want to keep the pool but you don't want to be held responsible if and when something goes wrong, I won't speak for others, but out of the few pools that offer solo mining, who would compensate a "missed block" worth over 100k? I am sure that no pool will do that.
So what is your responsibility and obligations? get a decent server, make sure everything looks technically correct, remove everything that is not important, Segwit, extra servers locations and etc, anything that might cause an issue should be removed, and that's where your duty stops, anything happens beyond that is merely bad luck, add a notification saying that "Due to many reasons, sometimes you may submit a valid block and the pool misses it, mine at your own risk", problem solved.
If I go to another pool, I won't trust them that they will do their best to avoid mistakes, I know you will, so mistakes do happen, I rather face mistakes with someone whom I know that will try his best to minimize them.
As for the fees, the first thing you should do IMO is getting the total cost per year for a server that will be MORE than enough to handle the pool operations, tell us about it, let's see if the community can fund it, as for your efforts and time, start 5% fees for your own efforts so that if blocks are found you get paid nicely, if not then you lost efforts, in other words, you did mine with your efforts instead of hashrate!( makes sense?), I don't think anyone will mind a 5% when they hit a BITCOIN block.
