If you provide greenhouse conditions over Winter it should not make much difference if the buds are forced now, or later. One requisite, however is adequate light to accompany any growth induced by warm temperatures. If the plants will be held in cold, dormant conditions over Winter, I would have discontinued any attempts at forcing the buds at the end of August. I find healed buds that aren't forced tolerate whatever temperatures the scion donor can withstand.
I strive to avoid late season newly emerged growth from being exposed to severe cold. If the citranges are fully hardy in your area, they should be able to tolerate the cold as dormant buds, but not as fresh growth.
I overwintered several dozen citrange bud grafts on Poncirus the past Winter without problems. The only catch was keeping the rootstock suckers removed in the Spring.