And mind that canvas frays, so it's really worth those fold overs at the edges...which makes it a bit of pain to sew
Decent needles....carpet sharps work well when sewing canvas by hand.
Probably best and easiest to suggest you have a look at JohnJames for those. 16, 17 or 18 Sharp is the needle you're looking for.
Afaik, they're still open for business, posting regularly and they've got a discount offer going too.
About a third of the way down this page shows the needles at actual size.
Buy the worlds best sewing needles for embroidery, needlework, quilting and all hand and machine sewing applications straight from the manufacturer - John James Needles since 1840
www.jjneedles.com
Basically you need strong, sharp, and with a decent sized eye to carry thick enough thread easily. Not a wide eye which would be a pain to pull through multiple layers.
For thread, it really ought to match the weight of the fabric, but an awful lot of modern cotton thread is carp. If you have something suitable for sewing jeans then that would do, but you'd be better either with heavy-ish linen thread or some of the polyester stuff sold for making/repairing webbing.
Barbour, linen thread....type that into eBay and see what comes up. Don't go too heavy, not mattress cord, even though that is superb thread.
More like this kind of stuff ...still a bit heavy, but bulletproof, iimmc ? I wouldn't put it through a domestic sewing machine, but it'll sew anything heavy and hold.
Large reel of Barbour's Irish Linen thread. 3 cord No 18.
www.ebay.co.uk
For polyester, this is the kind of stuff you're looking for.
SEWING BONDED POLYESTER THREAD. SUPER STRONG BONDED THREAD. 40's sewing machine thread. Simply the best Hand or Machine 40's sewing thread. NOT THE CHEAP IMPORTED CHINESE THREAD. DO NOT TRY TO BREAK IT WITH YOUR FINGERS.
www.ebay.co.uk
It does come in a range of colours, not just OD.
Best of luck with it
M