Like Annie I need to keep dry and warm. Weight, rainproof and breathabilty also matter to me.
I have not found any gaiters that I would be happy with weight wise, or that would pack down as easy as my trousers and also keep the rain out of my boots. In September, hopefully, you will not be needing a warmth layer, but the overtrousers were good for me in the earlymorning/late evening and easy to remove or put on as needed
Poncho (Rohan) 340gms;
Waterproof overtrousers (Regatta Amelie II) 320gms, after I removed the lining, were bought larger/longer than my normal size to come over my boots.
My old Regatta pair (weight 250gms), like the earlier Amelie version, had no ankle zip so were hard to pull on over my boots.