Gibraltar is one of the very toughest azaleas, good to zone 3!
A couple hints for aesthetic and survival. Cut off branches svery slightly convex vs concave as in other bonsai. Use chisels or a knife to finish smooth. Their wood is really hard, but the bark is thin compared to many bonsai. So a slightly convex cut will heal smooth vs a concave cut which will not.
Second, cut paste any cut bigger then a pencil cross section or a bit smaller if multiple cuts. Azaleas are very prone to
desiccation.
Finally, it’s better to leave a bit of foliage on a branch when cutting back if you want good assurance that it will grow. A hard cut with no foliage left on it has a hard time keeping the sap flow going and can die back. While a cut back leaving foliage has a much better chance of back budding as the sap flow is still kept intact, albeit at a reduced rate.
Well done,
DSD sends