90th day of playing the game, and I can say I'm quite satisfied with my list after the last 2 SBs I summoned (aside from me hitting, 29-30 people were able to get at least 1 hit in).
There are a few "outsiders" I intend to maintain as allies long term, special mention to someone named "jtkitty" who's been the longest-tenured ally on my list at 2.75 months. Before I discovered this Harem Battle forum, he was the only one, out of those whales I sent requests to, who bothered to pick up and carry this measly newbie (me!) 3 months ago. Never nuked unless needed (knows the RB/SB mechanic) and wasn't slacking on his rainbows (in comparison, I had a former ally with 3 rainbows that stayed at Lv.60 pre-evo for nearly 2 months that he was on my list, didn't work on evolving even at least one of them in that span of time, and I felt he was just wasting all that rainbow potential...)
Confirming Wutan's reply. I reached Level 120 yesterday and have 32 slots now.
Finally got around to accepting your request yesterday. Apologies if it took me quite a while. Zerana filled my only vacant spot last time around, and I had no one to remove on my list... so I tried to reach Level 120 as fast as I can to get that new slot. Good thing you still had space for me when I accepted.