If you can find a scanner I’d highly recommend doing it, but there are very few scanners that will do small flocks.
When you tried the powder, you did mix it with vegetable or sunflower oil didn’t you? Next year a harness is well worth investing in; you just slide the crayons in and off the ram goes.
Unless your ewes are Dorsets, I don’t think they would all be cycling at end of august, so the ram would likely have worked as a teaser for the first 2 weeks. So I would be expecting lambs beginning of February- not ideal if the weather is bad. Rather than keeping them out and bringing in at last minute (to a novice, the signs of imminent lambing can be quite subtle) id suggest bringing them in at the beginning of February and keeping them in until they’ve lambed.
Generally a ewe should lamb each year, otherwise they can get too fat and struggle to get in lamb in subsequent years. So if you’ve any empties that after 10 wks haven’t got in lamb, I’d personally cull them, but if you don’t scan you will have to wait to cull until they should have lambed.
Take your ram out now, and bring him into a small space with the wether to introduce them to each other- the wether shouldn’t fight but the rams hormones will be high and he is likely to try it on with the wether to show who’s boss. It will just stop the ram having too much space to hurt the wether.