It's good that you're wanting to start building bikes....but just be aware that people are passionate about them and don't like anything that can have a bad effect on the reputation of the fixed/singlespeed bike in the eyes of the general public.
What i said about position of the brake levers is made even more important when you only have one brake...if you can't get your first couple of fingers comfortably on the lever blade with your hand in the proper position,then the brake is both useless and dangerous...and any accidents it causes reflects badly on the reputation of fixed/singlespeed bikes and riders.
Spend a little bit of time researching what you want to do so that you do it well and safely.
oh....and 'welcome to the forum'...:)