i played hu sngs for awhile too (just to clear a bonus)
the biggest edge you can really have in these is probably winning 60% of the time.

i dont think this really helps your play much when it gets heads up in a full table sng unless you really have no experience heads up.

edit: that bonus i cleared was on tribeca too and i switched to there 6 person sngs and really crushed those to clear the rest. the full table ones where way to tubo-ish/high variance for me.