Holster recommendations for CC of a Ruger P-90

[Poodleshooter]

Any recommendations for concealed carry holsters from folks who routinely carry a Ruger P-90?
This would be for carry by a late 50's, thin built fellow, but in a cold northern climate. (I'm trying to narrow down the field of holster options available for my dad.) Good retention is a major issue for him.
Is OWB/paddle/beltslide carry practical with this weapon? It's sure a lot bulkier than what I carry!

 

[Khornet]

I carry mine

In the cool months. I use a Don Hume belt slide, called JIT Slide I think. Pulls it in nice and close with a good belt. Not conspicuous inder a jacket or polar fleece.

 

[Arub]

I normally use a IWB type holster. I have the Don Hume's M715 (about $18 in nylon and $26 in leather). They make the leather version with a retention strap, if desired.