Thought I would get some advice on this hand as I am still not sure about how I played it.

From memory
5 People Left, 4 pay, blinds 100/200 (about to go up)

EP -HERO - 3800
MP - Villian - 8000
Button - 12,000
SB - 3,500
BB - 800

I am dealt As8c

I am not sure I would usually raise this hand in this position but, table had been tight, too tight and most raises were respected. The two big stacks had not been raising enough and had let the small stack keep his BB in the last couple of circuits. I wanted to steal the blinds and stop SB from stealing easy money.
So far there had been no resteals (apart from by me)

I raise to 800.

Villain called, everyone else folded. At this point I am wary as villian had been playing tight.

Flop Js8s4s - giving me mid pair and nut flush draw. About the best flop possible for my hand.
I lead for the pot 1900, Villian pushes. I only have 1100 behind. To me this is an automatic call considering pot odds? and nut flush out.

Questions:
Would you raise pre flop with A8o from EP? If so how much? or fold and wait for better opportunities.
Post Flop, do you continuation bet, how much, should I have just pushed? or slowed down considering villians possible calling range?

Given the tight table conditions you discribe and most pf raises being given due respect I don't think your A-8o opener was bad at all. A-8o is a marginal opener from EP in a 5 handed tight table game (imo) but still vunerable and you want to keep that in mind.

A pf riase 4xbb is good for 2 reasons - 1. It's indicates you have a hand and are serious and the more marginal you opening hand is the more serious you want to look! 2. It covers the BB putting max pressure on the SS and show others you're prepared to attack him.

2nd CL is very tight and is the only caller - that can only be trouble. Although you have a pretty good flop it's still only 2nd pair just now (maybe 3rd if MP has an overpair) and you will connect on the flush only about 33% of the time. Being on the bubble with a SS - now with only 600 and in the SB for another 100 - this is a bad time to take unnecessary risks.
I don't like your flop bet for a couple of reasons.
> 1900 is 2/3 of your stack leaving you 1100 - less than your flop bet. You might as well have moved all-in as to make such a pot committed bet you can not get away from.
> checking into MP shows you didn't like that flop or are afraid of the 3 spades however leading out with a pot committed bet indicates you are not afraid of the spades or are prepared to bluff them. MP may have a Jx, a pp 99-AA, 2 spades or even the Ks -x. After looking at your leadout he should know you're likely to bet the rest of your stack off on the next bet if he just calls and that if he is behind he's only way to win would be to threaten your tourney life at the worse possible time - on the bubble! Had you checked, it is possible MP might have checked too or bet less than you did giving you a chance to see the turn at least or fold and wait out the SS to bust.
> Blinds are about to go up - more pressure on the SS who will only have 500 or less so becomes an easy target for any hand in the blinds. You can wait him out.

It's really frustrating to play from the middle stacks when the big stacks are not keeping the pressure on the shorties but that is a common occurance at SnGs. Certainly you also want to have a bigger war chest going into the money so you have a better chance of winning the tourney but attacking bigger stacks is usually ill advised simply because they can kill you and you can only hurt them. So depending on how bad you can inflict pain on their stack will determine how much respect they give you and/or how much they will put the pressure on you. Here you could have threatened half the villian's stack had you just shoved on the flop and it might have been enough Fold Equity to get the job done however if the villian has a hand or figures he can push you off with a threat of busting out maybe half his stack is worth the risk! The question you should have asked yourelf before betting the flop was, is this where I want to bust out on a chance to double up! If the answer was yes - push it all-in! Otherwise check it and hope you can get a free card or a clear choice to fold!

I like the fold preflop here, but after the flop you gotta go with this, you have many outs and are pretty much committed, esp with the blind moving up in a minute, it wont leave you with much

Before you're ITM, chip conservation should be your main concentration in SNGs. If the table had been tight, I'd only raise to 500-600 and get the same FE for less chips risked. If the table were loose, I'd just fold.

Because of your huge pre-flop raise and huge bet on the flop, you've pot-committed yourself against a tight player who likely dominates your A8s. The good part though is your flush outs and eight outs are likely clean, so you very likely have a good 11 outs and will make it by the river around 40% of the time. Your ace outs also could be clean.

To not get yourself in this mess in the first place, raise less pre-flop (or fold) and don't bet as much on the flop. Here you're nearly forcing yourself into taking a 40/60. Bad situation.