Hasaf -
If you plan to upgrade a Hicapa, you can make it look like the 1911 series. All you need to do is change out the grips and slide.
Example:

Although, there are many accounts of people using single stack 1911's and Glocks. The disadvantage of 1911's is their low Gas capacity and BB count. Hicapa has almost double the gas capacity and has 28 - 51 Round Magazine capacity while the 1911 is limited to roughly 24 BB's I believe. To be honest, any GBB will work as most GBBs out of the box will be able to cycle quickly enough before you actually acquire your next target. The only problem with not cycling fast enough is that rounds may not be chambered as fast as you can pull the trigger.