Not sure if they changed the ranges for return gifts or whether i have just been stupid lucky in the past few goes, but i did two runs of just putting in a single R-gacha ticket and got:
1st) x1 Card Reveal
2nd) Limited SR

time was 00:50:00, as per usual.

My latest attempts:

Pero Pudding x2, Peronamin x1, R Wild Card x1, N Wild Card x1
Time: 2h
Reward: Glasses x1
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Peronamin x4
Time: 1.5h
Reward: SR Wild Card 5 x1, Pero Pudding x1
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Peronamin x5, Pero Pudding HALF x2, SR Wild Card 1 x1, N Gatcha Ticket x1
Time: 2h
Reward: (R) Urumi Aiba x1
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Pero Pudding HALF x5, Peronamin HALF x4, Pero Pudding x2
Time: 1.5h
Reward: Candy x20, SR Wild Card 5 x1, Peronamin x1
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Peronamin x3
Time: 1.5h
Reward: Pero Pudding HALF x1, Pero Pudding x1
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Peronamin x2
Time: 1h
Reward: Pero Pudding HALF x1
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Peronamin x1, Peronamin HALF x2
Time: 50min
Reward: SR Wild Card 3 x1
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Peronamin x1, Peronamin HALF x2
Time: 50min
Reward: SR Wild Card 3 x1

Got 8 card reveals from that event, now i'm unsure how to use them. Used 1 + a R gacha ticket at first, but if i don't get the limited SR from that i am unsure how to proceed.

Should i use them 1 and 1 with an R gacha/peronamin or should i try to burn them all for a better chance?

I may be quite wrong on this, but I think you should try many attempts instead of a single big one.

Based on Chibikika's experience spending lots of Pero puddings at the same time, it was needed a lot of luck to get the limmed SR.
From what has been posted at the moment, there's a chance for really poor rewards in exchange of a big donation, but I don't know the limmed SR success rate for donations as big as 8 card reveals.

I'd like to wait and read more opinions, I'm in a very similar situation like you are, having extra card reveals and looking forward to get that damn limmed SR