993 oil tank venting question

[Jim2]

For those of you who have 993s with race motors how are you venting the oil tank?

Reason for asking is I have insufficient crankcase venting on my turbo project. The issue appears to stem from the tiny vent lines on the oil tank.

The 911/930 oil tanks have a 7/8" outlet vent on the filler neck, where the 993 tank has only one small vent 1/2". The other vent port has a pinhole, and the top vent has what appears to be a check valve. The three small outlets don't even ad up to one third the area of the large 7/8" inlet.