Bunker / War Mill: Frequency of follower items in work order crates?

[Sounder]

I'm focusing my Garrison on building up the follower team early, with the plan to replace some buildings later. I have Barracks, War Mill, Salvage Yard for boosting followers, and LM/TP for best production of Garrison Resources.

I haven't upgraded War Mill to level 2 yet, and here's my question: for those who've been running lvl 2 Bunker/Mill, what fraction of work orders result in a follower item vs. what fraction in a transmog-related item?

I have zero interest in transmog, so if follower upgrade items are infrequent, that's hard to justify...

Thanks.

[Zf]

Most of the time I only get 1 iron horde scrap, ive gotten 1 epic follower weapon upgrade and 1 legendary questline material once.

[Abujan]

I'm getting at least 40?% follower items, perhaps closer to 50% but it is frustrating getting that single iron horde scrap sometimes. I mean, I get 5-10 doing 1 dungeon compared to the 1 I get from the work order. 2/3 of the follower upgrades i've gotten from my salvage yard, but i have gotten an 630 armour and +9 weapon from the war mill.