Get someone experienced to try it, if they say its normal then you can start concentrating on your technique rather than spending time chasing issues on the bike which may not exist.
None of these points/comparisons you make are as important as how a bike feels to ride. Trying a bike is vital if you are thinking of buying.My advice is get the 250 which feels the most comfortable.
Don't overthink it, or spend too much time asking for peoples opinions on the internet. Everyones got different experiences.
Start by having a ride on the bike you're thinking of buying, you'll soon know whether it suits you or not. An EVO 250 is the default clubman bike, i'd start there, get a test ride.
Made in 1995 would make it a "works 295" model which pre dates the "easy", does it have have a perimeter frame?
Does it look like this: File:Works-scorpa.jpg - Wikimedia Commons
Always ran betas on 80:1 with a good quality synthetic oil. Thats plenty for trials use, you'll still get oil build up at that amount as you'll find out at the first big hill climb.
