Lovely project, where a lot of us are dreaming of to do the same.
That is a very big set of Sarissa, almost 8 kilograms (!) of weight, and with shipping it might cost more as 300 euro.
But it looks fantastic and now I'm waiting for more painted troops. Lot's of Imex figures but also what is availeble on the market as Napoleonic and AWI figures can be used for this project.
Found this page about the defenders of the fort on wiki. Very interesting read.
https://en.wikipedia.org/wiki/List_of_Alamo_defenders
And just like Keith I played this battle with my Airfix Wild West figures against my Napoleonic ones. And a strange thing happened, sometimes the defenders won, because there was some US cavalry that came in time to rescue them!
PS: and I would love to read those books!