Don't put a locker in a stock 27 spline Dana 35, definitely not with 33" tires. The axle is well known to be weak, will not be able to handle the stress, and it will break. Maybe not right away, but you will significantly shorten the lifespan of the axle and it will break at an inopportune time. Maybe on the trail, maybe while driving down the highway.
The Dana 30 can handle a locker much better than the Dana 35, but the larger the tire, the more stress is put on the axle.
Many people who want to lock the rear axle do a swap to a Ford 8.8 or Dana 44.