Cylindrical roller bearing

Desperate effort is required for outsider like myself to determine for action, disassembling the rear axles on both side of VW 1302 Super Beetle.

Judging from the illustration, the outer hub is supported by cylindrical roller bearings, on the other hand inner is done by ball bearings. Basically must I understand the reason and the difference role for the first. Both of them are sized, 62-30-20.
Because of preventing the lateral displacement, roller bearing is applied on outer portion? There must be some difficulty to set up them on adequate positions precisely?

Before ordering the bearing parts, outer roller bearing must be known what type of roller ones, at least three types exist in the category.

By the way,F3A Radio control invitational tournament, pattern aerobatic performance category should be held on 28th and 29th this end of month at Awaji Island model airplane airport? What has become of them? It was held in the Typhoon condition?