I started making my own bacon last year and for the first batch I'd recommend the wet cure method in
https://www.smoking-meat.com/make-your-own-bacon-at-home. Mostly because that is what I used for my first batch. The wet cure is simpler to do and lets you focus on other aspects of the process.
That being said, to answer your question on weights, you are on the right track. 1% salt means that for every 100 grams of meat you need 1 gram of salt. I prefer to use grams for all measurements involved in curing to reduce the chances of confusion. You are also correct about weighing the meat yourself. Nitrate/nitrite concentration is very important in curing and you don't want to trust your health to the attentiveness of whoever slapped the weight label on your food. I'll also add that when weighing, you want to use a kitchen scale rated for a max weight decently above what you are weighing. For example, the weight in the picture above is listed as 9.49lbs, which is about as much as I'd want to put on a scale rated for 11lbs. For weighing bacon/sausage meat I have a bread scale rated for 33lbs.
With that in mind I will try and give a step by step process for how to do the math. I will assume that the weight listed above is accurate.
1. You weigh the meat and the weight comes out as 4304.6 grams.
2. Convert the salt percent into a decimal so 1.5%/100 = 0.015.
3. Multiply the decimal amount by the weight of the meat so 4304.6x0.015=64.569.
3. Pay attention to the accuracy on your scale and round appropriately. A scale that displays down to the 1/100th of a gram might only be accurate to 1/10th of a gram. I usually round to the nearest 10th of a gram because even if the scale is more accurate trying to add or remove 0.1g of anything is an exercise in frustration.
4. Repeats steps 2 and 3 for all ingredients.
5. Do other stuff.
6. Enjoy bacon.
One last note. When I find a recipe I like I usually enter it into a spreadsheet that I set up so that I only have to enter the weight of the meat and it will automatically calculate all salt, cure, spice weights for me. It saves time when making it again.
And good luck on the bacon, once you make your own you won't want to buy it from the store again.