Ohhhh man Kanon was blushin' like crazy there
But is it a "Oh I'm embarassed to hold hands" kinda thing or a "GAY GAY LESBIAN GAY" type thing
Yes.
More seriously though, I'd say it's a lot more about being embarrassed/hesitant/reluctant about having to rely on her to such a degree than anything else. I don't think she's in the butterflies stage just yet, though I do think that she definitely cares a lot for Saki.
On Saki's end, yeah, girl's way past the point of no return. I hope this goes somewhere. I'll be honest, I have some reservations about payoff in Kuzushiro's works, so I hope this time they go big rather than home.
In any case, about the chapter itself - man, Saki is a gem of a girl. Big fan of how things developed. Not sure about that 'feeling' lil' sis has, though, I thought she caught on to Saki since their first interaction, so what else could she be worried about? Also, her attitude's really growing on me.