Several folks here recently said they have mixed radial and non-radial with acceptable results.
My experience when a dealer put a non-radial on my front while I had a radial on the rear was not so good. I noticed the handling of the bike "felt" a bit "off" for a week after the new tire was installed. I then discovered the error and the dealer replace the front with a radial. My bike was a 2000 K1200.
BSA 650 about 1969 Used, Denver, CO
Harley 350 (yes they made a 350) New, about 1971 Denver, CO
BMWs owned in sucession since 1975
R65 Used, Denver, CO
R90RT New, Denver, CO
R100R New Spokane, WA
K1100LT New Spokane, WA
2000 K1200LT Used, in 2001 then another
2000 K1200LTC Used, Canyon Red Metallic in 2003 then another
2000 K1200 LT Icon Used, Canyon Red Metallic in 2011 and still rolling.