Dave - Feed them 1:1 sugar water. But make sure it is 1:1 only. If it is anything stronger it doesn't stimulate them to pull wax. Instead anything heavier will only put them into storage mode and they will store it away and ripen as honey inside of the brood nest.
In spring stimulation with 1:1 will cause the new bees to start pulling wax. However, if there is a problem such as queenlessness it will be the same as heavier mixes and they won't draw wax till it is required to store more honey.
So with that said if you are queen right, 1:1 mix by the pound - 8.63 pounds sugar to 1 gallon water. Creates about 2 gallons of mix. Should stimulate them to pull wax, if you are into using essential oils or a good brood builder like honey b healthy don't forget to mix it in too.