Re-checked by statement earlier btw and reducing offset actually increases trail. So, you'll be fine.
1/2 inch reduction in offset won't affect the trail a whole lot anyway. Stock trail is like 3.8" IIRC. Looks like 1/2 inch offset reduction should put your trail in the neighborhood of 4.2"
BTW I should have said earlier "Four to six inches of trail is the target zone that a lot of chopper builders go for".