I used these https://led.cdiweb.com/ProductDetail/47319203050-BJB-GmbH-Co-KG/592663/ in particular. $1 each.@tomate Here are your holders-https://led.cdiweb.com/LED-COB-Connector/ProductsGrid/11143#null
Careful, it says pulsed, so you need to adjust to get Tj=25. Lumens will be a little higher.Thx for the links guys.
So for example taking the CLU058-1825 3000K 80Ra, according to the datasheet the lumen output at Tc = 25°C is 18931.
18931/328.32*4.867 = ~280
The table provided by citizen says 249.
So you have an address in Poland? Too bad I don't. I contacted them and they told me that they are not allowed to ship or to sell to Germany, nor will they do in the near future. Seems like they have no rights to sell them to Germans. Digikey is no option at the moment, the same chip is currently listed for almost 30€ each...I've send them a message today.
Funny thing is, after changing the language to polish which sets the shipping destination at the same time, the price drops. At the moment I would pay 11.80€ a piece with taxes and shippig costs.
So that is ~270€ for the 23 pieces I would need.