Received a mail form HeliDirect that the heatsinks are back in stock:
http://www.helidirect.com/product_in...oducts_id=1508
I discovered they also have another type of heatsink that might work for the 4#3, hadn't noticed this one before, maybe it's a new product:
http://www.helidirect.com/product_in...oducts_id=1771
I ordered two of each type, will report back about weight and performance...