Between the Royal Enfield Classic 350 and Meteor 350, the former would be our recommendation. The Meteor's feet forward position will transmit more jolts to your back over bad patches of road. Therefore, it won't be comfortable over long stints in the saddle. The Classic's upright and neutral rider's triangle will be easier to live with on a day-to-day basis. 

You should also take a good look at the Honda CB350 models because they have a similar riding experience to the RE 350s. But are much lighter and come with alloy wheels and tubeless tyres. They also have a slip/assist clutch, resulting in little effort when operating the clutch. 

Since you are a taller person, looking at an ADV like the Hero Xpulse 210 and TVS Apache RTX 300 is also a good idea. Of the two, the RTX is the better all-rounder, but the Xpulse is lighter.

Take a test ride of these bikes so you can decide which is a better fit for you. 

The Honda CB350 trio are very similar machines and we would recommend choosing the one you like the look of the most. These are plush, smooth, proven and reliable machines, although don't expect too much in terms of performance from the relaxed, long-stroke single-cylinder engine. 

For similar reasons, the Royal Enfield Classic / Bullet / Hunter are also worth taking a look at. The first two will feel more substantial and have more spacious ergonomics. The Hunter will feel much lighter and more compact in comparison, so depending on the sort of bike you want, you should choose between these three.

Finally, the Guerrilla 450 is a far sportier and faster bike than these slower 350cc models we've suggested above. If this is the sort of riding experience you're after, it makes for a good purchase.  

Since this is your first bike, we'd recommend taking a proper test ride and seeing which one is best for you. 

In the 350cc category, bikes like the Royal Enfield Hunter / Bullet / Classic 350, Honda CB350 trio and TVS Ronin - which is smaller but has comparable performance - are our top picks. Pick the one you like the look and riding experience of the most because all bikes are proven machines that will last you a long time. 

If you want something with a low seat height, the RE Hunter (790mm), Meteor (765mm) and Goan Classic (750mm) are your best bets. 

A test ride will help you decide.

Considering your usage and budget, you can look at bikes like the Royal Enfield Hunter / Bullet / Classic 350, Honda CB350 trio, TVS Ronin and the Hero Xpulse 210. All have spacious seats, comfortable suspension and have decent braking performance too. A test ride of all these machines with your wife sitting behind you will help you decide which is the right fit for you. 

Do bear in mind that making the switch from a scooter to a motorcycle will need good hand and foot coordination to operate the clutch and gear pedal.  We recommend you practice on a used bike first before taking the plunge.