Jemimapubbleduk - (love the name by the way!!!), I thought I would answer here rather than the other thread.
From my experience, my hcg levels seem to go down at a steady level of halving with my m/c's. Be it quick or slow. I have had 11 miscarriages (14 pregnancies).
when I have stopped bleeding before passing all the products of conception, I have found that it is when my hcg levels reach zero (or near!) that I start bleeding again. But with the one that I passed 4 weeks after stopping bleeding, my levels were not being measured, all I can say is that my pregnancy tests remained positive but were getting slowly lighter as the 4 weeks went on. I would guess that I passed the sac (8 week size) when my levels reached around 100, but within 3 days my tests were negtive having passed it. The pregnancy I reabsorbed I was only 6 weeks pregnant and took a month for my levels to decline, I had a bleed once my tests turned negative.
If you were 700 on friday and still at 480 on monday, your halving time is more than 5 days, so to half to 240 will take til Thursday, then 120 take til the following sunday, 60 the following wednesday and ..... you get the idea, so you are looking at possibly another few weeks unless the halving time speeds up (which it can) until the products are reabsorbed. But there is a chance you could bleed before this and pass it with the next bleed.
The problem is making sure that you watch out for any signs of infection in that time. I can understand the trying to avoid another eprc for risk of scarring.
I only had medical management once and it did not work! I am sorry you are having to go through this horrible time.
I hope that things sort out for you soon.