With respect to OP, i dont want to hijack, i want to answer it quickly and move on, if you have other questions about the seoul chips please start a new thread
Tell me what u no on theezz xhips
those are 38x38 cobs just like the citizen clu058, so they can use the same holders i have at my site
a lot of manufacturers make chips in standard sizes
all these manufacturers make 28mm and 38mm chips that take the same holders:
28mm: citi clu048, luminus CXM22, vero V22, seoul SDW06, getian, at least a few more
38mm: citi clu058, luminus cxm32, seoul SDW07, getian, etc
buying heatsinks compatable with either a 28mm or 38mm chip are a strong buy as all these mfrs are pulling hard on development right now so its possible in a few years that seoul pulls ahead and eclipses luminus and citi in efficiency. In any case all of these mfrs. should have current offerings in that size
unfortunately seoul only offers that chip in 5000K which is a poor choice for flowering. according to datasheet its 140-145 lm/W at 93W which is alright but nothing super exciting imo.
28mm chips are generally more popular than 38mm chips as they are typically a lot more cost effective, as well as having a lot more options for holders and reflectors (there are no reflectors for 38mm cobs unless you mod reflectors or holders)