far as i know your 4 yr olds havent been outside ever. a bit tricky,as i heard of some adult old wdragons (ex ak zoo ) that have never been brumated (under heat all year round) . that died over winter when finaly brumated outside.... i think your on the right track for this winter BUT NO FOOD! next spring /summer get them outside so they can acclimatise to big temp variations n they will be good to brumate outside next winter. i got this years babies,yearlings n adults all brumating outside now,they have all been outside from day one....you will also double there lifespan.
example iv had a male wdragon outside from day one,will give 99 to 100% fertitlity...iv had a male wdragon,hand reared inside for the first 18 months,grown too fast too hot(not by me) was approx 600mm total length by then.then moved outside ,5 years on, still only approx 20% fertility, offspring just as healthy as the other,male wdragon just as healthy as the other, but fertility down.....once the fertility damage is done,its done....in saying that once outside, you will still get a longer lifespan n healthy animal . if you cant get them outside,less is more with heat. outside in summer they hide from the miday heat,and are the most active mid to late morning then late arvo. i start feeding mid october n stop feeding late march early april.weather dependent. i hope this info helps...