Increase range??

The size of the spear and amount of force will give a little more range, but not as much as a 130 and not so much before the gun doesn't shoot as accurately.

I would get a longer gun for situations when you need it and let the 95 shine for situations when a short and more maneuverable gun is called for

The lenght of the gun should be proportional to the visibility of the water where you dive and the type of spearing you preffer.

A 95 will never have the range of a 130, no matter how many bands you put on it.

Sometimes is good to have 2 measurements of the same gun because you have a "hole" gun and an "open water" gun with the same handle, which means no adaptation when switching from one to the other.

I would use that speargun with a 7 mm shaft and 2 x 16 mm (or 14mm) bands.

A reel doesn't give you any estra range. It is a "line storage device" used to play a speared fish from the surface.

A speargun needs to be balanced for the best performance, and that is "balanced" in an all round sense. Longer range usually requires a longer gun, powering up short guns does not compensate for the lack of increased sighting radius on the short gun, but of course it depends on how much extra range you need. A harder to load gun means you will invest more energy in the shot, which means more to you when you miss! Buy a longer gun and keep the shorter one for the conditions where that is all you need.

One of the things you'll need to do to increase range on a shorter gun, is use 2 wraps of line.