Just made my expansion purchases.
I've tried planning it out carefully.
I worked out that to field the Forces (with variations) that I wanted I needed:
2 Banner Bearers for each faction, 2 Musicians each, 1 Champion each and 1 Wizard each. Rather than purchase 2 Infantry Upgrade expansions each I just bought 1 each; for the other 4 figures I needed I'd found a shop that splits boxes that didn't get pre-ordered, the individual character figures were £3.95 each and the 1 upgrade I did want a second copy of was £1. So to get everything I wanted (over the 1 box each) cost me £16.80 rather than the £40-£50 for a second expansion for each faction.
Unfortunately all the Reanimate archers and Cavalry had been pre-ordered so I wasn't able to buy individual upgrades from their expansions.
So as the Reanimate Archers has a Waiqar only upgrade (which will probably only be in that box) I bought an expansion; not that being able to field 6 trays of archers (I bought 2 core sets) is a hardship.
For the Cavalry, however, I'm happy at the moment with 4 trays and as none of the upgrades are Daqan specific I will eventually end up with copies of them since I will be collecting all the factions. So no Cavalry for me this release.
As I'd like to be able to field 2 3x2 units of Reanimates with full upgrades I decided to buy 4 Reanimate figures for £5. This is actually 2 more than I needed to but it will allow me to field the units without all the figure upgrades if necessary. I didn't need trays for these as I'll use the trays that come from the Infantry Upgrade expansions.
Finally since I was placing an order I bought a Carrion Lancer and Rune Golem (£22 total) for which I'll use the spare trays from my second core set's heroes. This will allow me to field 1 Support Model in a large infantry unit and still be able to field units of 2 models (4 once the Carrion and Golem expansions come out).
Just the waiting for them to arrive now; oh and putting them together, and the painting.....