Not sure what you are going to gain with early imports of Queens or packages?
On another thread you said you have 3000 production colonies(?). If your winter losses are say 10% that's 300 colonies you need to make up in spring. Surely you can make these up just as quick if not quicker from your own over-wintered nucs rather than import queens or packages?
By anticipating the winter losses it would be more sustainable to raise your own nucs as replacements?
By importing queens to increase your stock rather than to improve your genetics I presume the motivation is purely financial?
I suspect you are unaware of what goes on at our place as the last sentence especially is totally off target.
For our own unit that's exactly what we do. You can see the pictures of the nucs and mating unit on my twitter feed. We have not used packages in our own unit, bar a FEW clients failed to stump up for or were 'no show' at collection time, for a few years now.
BUT
The bringing in of the packages especially was started off as a 'common good' project where I used my connections to get all those in difficulty locally bees at a fair rather than inflated price. Not everyone can sink 100K into a project and even then, if you are obliged to fulfill a pollination contract (some of our overwintered nucs are sold to such people) and have a clause that means its costly if you don't meet the contract...then you need bees PDQ in April or May to meet that demand. Spring packages can build up on the OSR, and sometimes even give a super or two of honey. The demand has continued, but has shifted more to the SE of the country, where pressures for earliness are strongest.
Then there is the issue of WHY there are these spikes in demand. Its usually because of a big die off, which periodically happens across the country (and other countries too, its not just a UK phenomenon). When it happens to the main colonies in a unit it happens to the nucs too. They are a great tool which makes up the losses before they happen in more years than used to be the case, but as in the last main post....nuc success broadly correlates with colony success.....so local dependency when there is a local die off is a risky place to be.
However, an early queen DOES have a load of advantages. As a 2017 example..we took over running a stack of empty hives (Langstroth and all our overwinter nucs are on BS frames for now) so had to get them up and running asap. We took TWO bars of brood (mostly sealed) and bees and a bar of stores from some of our existing Lang hives at the start of May and put them into 5 bar poly nucs and fed them. We used queens raised for us in Piemonte, mainly but not exclusively from our own breeders, and introduced one to each nuc. In only a week the two bars of foundation had been drawn and they were across the box so got promoted to full hives. Fed again. By the end of May most of these required to be doubled (then fed again...that's a serious gap time here). Of the 96 on that group 85 went to the heather in late July as triples and gave about 35Kg of heather honey. Cant be done *just that way* with queens much later. Changes it from an activity that costs into one that pays, and the bees are great and healthy too. Into winter right across the box.
The same exercise repeated four weeks later resulted in an average at the heather of 9kg but still very good hives into winter.