I actually would buy a dedicated R5 row if everything else was normal. Not sure how many sets have an R5, but I feel like it's not common.
I think all previous “Alert” sets were R5 with no Alert row in Base.
Looking at GMK sets back through 2024, only two had R5 bottom row and some had Alert row in Base.
GB end : GMK Sets with Alert row : Bottom row : Alert or Non-alert in Base6/'26 : GMK Prussian Alert : R4 : Alert
4/'26 : GMK Green Alert : R5 : Non
11/'25 : GMK Monochrome Dolch : R4 : Non
5/'25 : GMK Violet Alert : R4 : Alert
2/'25 : GMK Lilies of the Valley CANCELED : R4 : Both in Base
9/'24 : GMK Blue Alert R2 : R5 : Non
6/'24 : GMK Rubrehose : R4 : Alert
4/'24 : GMK FTRO : R4 : Non
Sets other than GMK:
GB end : Non-GMK "Alert" Sets : Bottom row : Alert or Non-alert Base6/'26 : SWG Rainbow Alert : _?_ : Both in base
6/'26 : DCS Dream Alert : R4 : Alert
4/'26 : KAP Grey Alert : R4 : Both in base
11/'25 : DCS Pink Alert : R4 : Both in base
8/'24 : DCS Lam Alert : R4 : Both in base
8/'24 : DCS Red Alert R4 : R4 : Both in base
GB end : Non-GMK sets with Alert row but not in name : Bottom row : Alert or Non-alert Base6/'26 : MW Meteor Dreams : R4 : Both in base
6/'25 : SA A History of Violets TKL base : R3 : Non
6/'25 : SA A History of Violets Full base : R3 : Alert
4/'25 : KKB Lilies of the Valley : R4 : Both in base
4/'25 : PBTfans Lucy R2 : _?_ : Non
4/'25 : KKB Soju Blue : R4 : Non
3/'25 : TUT YakeyIt : _?_ : Non
2024 : 8 sets with Alert in Base
2024 : 7 sets with Alert in Child kit