Peter,
The best solution is to shoot your G34 as a production gun. Glock 34 &35's are legal in production class. This was addressed in the Front Sight July/August 2002, page 5:
"This has been answered in previous Front Sight articles. Yes, the Glock 34/35 is legal in the US production division. IPSC has a five-inch barrel lenght provision. We do not, but the gun must fit into the IPSC box, which the 34 and 35 do."
Hope this helps!
Jason
www.magiccityactionshooters.org