Hi Jewels.
While both beds you listed would be good quality/value for your BMI, I’d keep in mind that 4" of memory foam will not feel the same over the entire course of the night because of memory foam’s temperature sensitivity, which of course is also dependent on body and external temperature, humidity, and time spent on the foam. All memory foams, even the ones that are firmer than others (they range from an ILD of about 8 to about 18 although ILD is not that significant with memory foam), are considered to be soft foams and the biggest variable is how long it takes for them to get soft. This is why memory foam cannot be used as a support material in a mattress (it’s only used in the top layers) and there is always a different material used under the memory foam to support the weight of the body. Memory foam is a slow responding pressure relieving material.
Also while 12.5" thick mattress is not necessary unless you like a tall setup you can read more about the effect of thickness in post #14 here. Regardless of how thick or thin a mattress may be, the most important part of the “value” of a mattress is how suitable it is “as a whole” for your particular body type, sleeping positions, and preferences in terms of PPP (Posture and alignment, Pressure relief, and Personal preferences) regardless of how thick it may be. There is certainly no reason that at your weight you would “need” more thickness, but you may still “prefer” a mattress that is thicker or thinner depending on the design and layer arrangement. I’d make sure to call Nest Bedding and ask them to assist you to ensure the best chance of having a good firmness fit. They are extremely helpful and consumer oriented and like all the members of the site I think very highly of.
Thanks for your holiday wishes… I’ve had a very enjoyable time, I hope you did too 
Phoenix