That looks like you either need a few mm wider tape to account for the trough or try that thinner tape to build up the trough to allow the wide tape to seal ride up to the hook of the rim.
The tape needs to be below the bead of the tyre to seal properly.
This 21mm wide tape in my 21mm internal rim you can see is a very close fit, a 22mm would work but it would be very time consuming to get it lined up perfectly. It's hard enough with this 21mm and certainly the couple of times I've gone off centre I'd soon been able to tell - the 'free space' is less than 1mm and only marginally over when working it into the trough.
The thinner tape I'm expecting it to fit into the trough without having to fight with the taughtness of the tape between the bed 'shoulders' - as the thinner tape won't reach both of them. Part of me wants to do one loop on each side of the trough to get it perfectly stuck in the bottom, but I don't want the issue of the tape not sticking well on the overlap and causing me leakage that way (as that tape on tape interface becomes the weakest part of the whole setup).
Take old Tyre off keep sealant in it, put on new tyre, mount 90% of it, pour sealant in. Done.
Jonny I haven't had any issues with overlapping tape and the seal has been just fine, but I believe it is better to avoid the bead.
No old tyre, or new tyre. Same tyre! Bought 10*10ml syringes, with the 2-3oz roughly translating to me putting 70ml of sealant in there... Then after the overnight (only air) leakage I put a couple more in... So around 90ml of sealant in there!
Good hint to get syringes to put it in though
@touch ! They worked so-so well, also make it really easy to get the required amount in there... The time it took to get 7 full 10ml syringes in there is making me think my 'pour' and measure (from the side of the Stans bottle) I did for the first wheel - that I put nowhere near enough in there!

Once I've sorted my tricky rear I'll hopefully have the method figured out and will re-do my front, while also adding enough sealant!
EDIT: Just to note, I've had zero real issues getting these Specialized Roubaix Pro '2bliss ready' tyres to mount on these rims with a track pump.
Although they're so damn tight that even with the bead in the centre of the bed it takes 3-4 tyre levers to get the last 20% of the bead over the rim. Can just about get 1 lever under 1 bead with the tyre mounted, but not the 2 required to get enough tyre over to unmount. Have to push/lever the bead away from the rim into the centre of the bed as a first step, then get 2-3 levers under it to get it over the rim enough to unmount!