Jupiter squares are much more likely to influence weight gain in the way of making you fat by, for example, increasing your crave for sweet foods and making it irresistible.
When it comes to gaining something, you should use spiritual tools only in a way to put your mindset in the right place or, otherwise, to turn the odds in your favour. Using it for direct physical effects will not have the desired effects because a material vehicle is needed for the working to manifest. Not to mention, it would instil some kind of Harry Potter belief that you don't need to act in the physical world but everything is going to sort itself out because you're chanting. This is a deleterious mindset which just doesn't work in reality because it's not based on natural law.
Your working needs to be balanced by adding healthy exercise and healthy nutrition into the equation.
Take a picture of your ideal body shape by looking into example from your race, your height and bone structure. Photoshop your face on it, then print that picture and put it somewhere you can always look at around the house. Also keep it in your phone, somewhere that is easy to access.
Next, think about what type of exercise can build that shape. Are they lean, defined and strong? Then you may want to look into gymnastics-based programmes like Gymnastics Bodies (or artistic gymnastics itself), swimming or any other sport that is associated with a lean, powerful body. Are they bulky? Then you may look into sports and training styles that build a bulky body such as cross-shit, ego-lifting and more.
From the nutrition point of view, look at what athletes in that sport are eating but also look at what your level of activity will be. Look at many relevant cases, not just one or two. Look at 100 or more. That's how research is done. Regarding your level of activity, that will determine how many healthy carbs you need in your diet. With little to no exercise as well as less than 4 hours of high-intensity exercise every week, you don't need many carbs so your diet should be fat-based instead with moderate protein and low carbs (like 25% max).
The website "Damn Ripped" has a great TDEE calculator, but you'll need to then set your own percentages to divide the macros as it can easily lead you into over-eating protein and carbs. I would just take the TDEE value. TDEE means Total Daily Energy Expenditure, meaning how much energy you expend on a daily basis. The reason I'm promoting this calculator is because it's the only one I know that not only allows you to base your calculation on your on lean body mass but also has two different multipliers for activity and exercise. It is important because your exercise factor as therein named is relevant to how much you exercise while the activity factor is your lifestyle without exercising. Lumping them together into one factor only increases error as an average is estimated.
Drinking is also very important and it depends on weight. See my other posts about drinking to understand how much you should drink, which is not 2 litres a days as wrongly advertised by enemy media and broscience.