You really need to creep around here and read up on a bit more stuff.
There are a pile of factors that you need to consider in regards to taking on the role of a sniper.
Your search for a pistol is showing somewhat that you need to research this out a slight bit more.
Talking to other people who game that role in your area is a good start but also a poor one because what works for one player does not always work for another. And researching is good also but it doesn't seem like you've done enough, not just yet anyhow.
Having said you've held various AEGs and none of them fit or felt right, keep trying them.
Even the guys here (locally) who run a "dedicated" sniper role (I put dedicated in quotations because very few guys here run with just a sniper rifle as their main platform) always have an AEG to use for when that time of need arises.
Having a pistol for when someone gets in your MED is great but if someone does get in your MED and you've only got that pistol cause you can't use your primary weapon. You might as well kiss your ass goodbye. You'll be out gunned and unless you've got some John Woo inspired moves then...well, you get the idea.
As it has already been pointed out, the pistol you're thinking about is cumbersome looking, and Wetech can be hit or miss at the best of times. Some people have had great luck with their stuff and swear by it. Other people loath the brand and will tell you to stay away.
If you manage to find the pistol, get it, and it works for you great.
If it breaks and you end up hating it, then what?
I think you're selling yourself short and you should keep looking at pistol options.
If you did get it what holster are you going to get for it? Are you going to wear it on a thigh rig? Chest rig? Have you even thought of that?
The reason people suggest an AEG is a simple one. You are less limited when you're just getting into the hobby.
Sniper rifles usually run hotter than AEGs on a field. New plays have this wide eyed aspiration to run a hot gun because (and I think this is it) it bestows magical sniper powers to them and makes them an invisible bane to all other opposing players. Yes? No?
Reality is, they think they'll be out gunning the guys they're shooting at and anyone with a few seasons under their belt will tell you that just isn't the case.
I applaud the effort you're making thus far but keep in mind, what you think will work for you when you start is going to be totally different from where you end up.
When I started I had an idea of what I wanted for a gun, pistol and kit. I was given solid advice that (like many new players) I chose to ignore. I wasted time and money realizing that I should have listened to the seasoned guys.
You may start out with aspirations of becoming a great airsoft sniper (and who knows you just might) but remember others started out like you...and then they took an arrow to the knee.
lol