@numiru: Don't make full kits for 40%/60%/TKL , this is not a good approach, it will only split the orders and lower the chances to reach the MOQ.
From watching other GB's matt3o has the best approach.
1 set for ALPHA (where you can include also the 1u |\ key )
1 TKL modifiers set (that can be used also for 60%) (this includes F1-12, navigation, PG UP/DOWN etc, 1.25 on the bottom row with 6.25 space bar)
1 40% modifiers set
1 Numpad set including also a top row (for multimedia or something like that, have a look at Midnight for inspiration)
1 Tsangan ( 1.5 mods, 1u Win/Menu, 7x spacebar, Short 1.75u right shift, 1u FN, HHKB Style 1.5u backspace
1 ISO Kit (ISO Return, short left shift and the 2 extra keys, don't know what's on them, I'm not using ISO, but a lot of EU guys will love you for that
And optional, I like this one the most, but that's me: Caps lock replacement kit : 1.75u Control for people who like the HHKB layout. You could include this one in TKL or TSANGAN
You could make an extra kit with some weird sized caps, I would not include them in other kits because it might raise the price too much.
The best thing is to try and get the best price for each kit, too many options increase the price and people don't buy it.
And would skip the blanks, some might get upset, but based on statistics blanks never hit MOQ (or only on rare occasions) and would only split the orders.