So sorry Animom, I've been away from these forums over lent and only just seen this
How are things going now? To try and answer some of your questions - if they're still relevant...
Tbh I'm not an expert so please take anything I say with a pinch of salt. I know LOs can get much more efficient at feeding as they get older, although mine would tend to either linger or get distracted! I'm not really block feeding any more but lots has changed as her tummy's presumably bigger and she's on solids, so I wouldn't know what colour her poos would be without the solids now. I did have a dip in supply when we both had flu in January, so ditched block feeding temporarily to get it back up again, and settled on the feeding pattern below when we started getting green stools again (solids weren't properly established then).
Feed 1: R
Feed 2: R then L
Feed 3: L then R
Feed 4: R (BT)
Feed 5: L (df)
I found that the right side seemed to do her for 1.5 feeds and the left for one, iyswim? Now we've just ditched the df I'm offering the left at BT too, so I've ended up offering both sides at every feed, but starting with the same side which I used last, so she gets the fattier milk first. That's just us though, I'm sure you'll find many variations on here! I only found out about the tongue tie and silent reflux when I saw a lactation consultant about the green stools and slow weight gain, she was 3mo by the time we had it divided, I'd already started block feeding by then.
How's DS doing otherwise? Weight etc? And how old is he now? It's quite normal to feel less full and feel like they're feeding less around the 6mo mark, when actually I think they can just be more efficient and you just make what they need each feed without filling up so much in between or something like that?! HTH? So sorry for the delayed reply.