Please please hun, do not try to get into this business without a nail trainer, yes they are expensive but worth their weight in gold.
I offer L&P not gels and on that score I think you are right, master one type of product at a time.
Get your yellow pages out and ring a few salons, tell them you are asking before getting into it your self and want to know what % of clients are L&P and which gel then go with the most popular.
I love the idea of your summer house. A seperate room, especially when you have kids is always a better option, you can leave things set up, no one is going to knock things over, kids friends aren't going to touch
etc
But the training kit is just that, even creatives which is very good, needs topping up before the end of the course.
In your shoes I would want the biggest summer house I could fit in my garden, and have a good slush fund for extra products, I think its lovely that your hubby is so involved and wanting to back you up, so many partners cant understand how much you need to start up, but I would ask him to sort out your advertising, leaflets web site ideas etc with the thought that ladies want to feel special and your summer house on the front of your leaflet/homepage is a lot classier then your kitchen sink:lol: