So many questions and so little time but I know I’ve come to right place; help please!

I have done the math (very successfully) for the Butter Cakes of various sizes but only for round cake pans. No fear I think, I’ll search in TCB for what to do for square cakes. I’ve read the directions and did the math once more and I think I’m on the right track but I want to verify that I understood everything correctly. I see that a round cake pan is only 3/4 the size of a square cake pan and therefore you need to multiply by 1.33. I did all the calculations (example 8 inch pan) base times 3.5 then after that I multiplied the measurement by 1.33….is that right? (base of 1/2c X 3.5=1 & 3/4 c…then 1 3/4 X 1.33=2 & 1/3 c give or take a smidge).

I have another question as well, the 8” pan falls in the level 1 baking powder (which is .28 oz per base which is .28 X 3.5 = .98 oz ). Now here’s my big question: do I take the amount of baking powder (i.e. .98 oz) and multiply that by 1.33 as well? So .98 X 1.33=1.3 oz?? I have read soooo much in the last little while in preparation for this cake that I am totally unsure as to what I should do. When it’s a larger surface area you decrease the baking powder…right? I’m very concerned that I could seriously goof up the cakes if I put the wrong amount of baking powder in (especially with the larger layers {12”} planned for this cake).

Now as if I haven’t asked enough questions I have a few more

For the amount of batter (by weight) for each pan; is there a way to figure out how much to put in each pan? Do I just take the weights for the round pans given on page 490 of TCB and multiply it by 1.33 or am I making it a little too simplistic? As well, any hints about baking times?

I’m going to be using fondant for the first time and I think I’m as prepared as can be expected when it comes to reading every book and blog known to man. The main question that remains is what type of buttercream to make. I have made a Swiss Meringue Buttercream (Martha Stewart) and it turned out but I wasn’t crazy on the texture or taste. This might be sacrilege but it there anything that anyone can recommend that has a different texture? While on this topic, is there a rule of thumb for the amount of filling needed between layers of a square pan (I assume the chart on page 513 is for round cake layers).

I think that’s the end of my questions for now but I can’t say it will remain that way for very long. I would really appreciate any and all advice!

**Thanks.**