Trouble marrying my DWPS and UWPS. Techniques

All my life I’ve been a downward pick slanter with my right hand fingers being more open. recently I’ve been getting into playing Bluegrass guitar and a lot of the vocabulary is played with more of an upward slant and I find myself more comfortable with the closed fist when I’m playing those type of licks. The problem is that when I go to switch to downward my technique, doesn’t seem to match my upper technique and so I’m having trouble unifying them. I feel more comfortable, arching my wrist and rotating my arm like Eddie Van Halen on the downward picking, but that technique doesn’t work for upward picking for me. When I try to remove the forearm arch I feel a lot of tension in my DWPS.