[lutman]

Dip stick issue looks as if all ok now ?
ref the reservoir fluid - no matter if remote or attached, the lowest point of the reservoir should be higher than the highest point of the master cylinder.
basic fluid dynamics - if the reservoir fluid level falls below the master cylnder inlet then a low fluid level could permit air into the system.
A master cylinder with reservoir attached is usually the best way to go as it eliminates any additional pipe work or fittings that could cause leaks or trap air. Downside is usually the size where space may be limited. suspect thats why its recommended to use a remote as this can be located somewhere more accessable for filling