1ml per litre will be fine. Autumn feeding usually involves 2 : 1 mix of sugar to water.
Hivemaker has tested this to a maximum of 10ml per gallon with no harm to the bees.
.
Drove to Scorton about 24 miles from home. Had a walk by the riverside and saw huge swathes of balsam, the noise was incredible.
There is none near my hives. :o. :cuss:
.
As you say the thymolated syrup will do both. The German sublimator on eBay is a decent device, it also works using a glowplug. Plus they tell you which one replace it with.
.
If they appeared earlier this year and you still haven't got around to finding them, then they can't be that much of a problem. Why don't you leave them?
Seems a shame to go fishing around for them now.
.