Hoping to make my way out to Rainier early next summer (May probably), and looking for some input on insulated jackets.  I have a lightweight OR Fraction jacket ( OR Fraction Hoody ) 
, a MH Sub Zero Parka, and a MH sub zero vest.  I am usually fine with the ultralight OR primaloft jacket down to the teens, but from what I've seen, something a little more substantial may be in order.  However, the sub zero seems like overkill.  Any thoughts?  Maybe combining the vest and OR jacket?  I'd rather not buy another jacket if I don't need to, but if anyone has high recommendations for a mid-weight insulated down/synthetic, it may be worth it.