I understand the desire to do some small test batches and I hesitate to bring it up since it has nothing to do with your original question and I have no idea what your constraints are in terms of equipment. etc. , but I would suggest trying a bigger batch - maybe something like 3 gallons. A 1 gallon batch will yield you 8-9 bottles of beer and will still take the same time to boil, ferment, and condition as a bigger batch. If it is a great beer you'll hate the fact that you only have 8 bottles. Even if it is a good beer, you'll wish you made more. I've moved away from 5 gallon batches and do mostly 3 gallon batches now. I do partial mashes and partial boils and this allows me to use more grain and less extract and do closer to a full boil than if I do 5 gallons. I get about a case of beer give or take some.
Basically, I'm saying I understand and like the idea of scaling down, I'm just not sure scaling down to only 1 gallon is worth your time and effort.
But if you do go ahead with 1 gallon batches, I definitely agree that you should try to do a full boil.