Some engine mounts may appear small when gluing them in. Most introductory kits may have some parts looser than other kits to allow the beginning builder some allowance for error. This will not be a problem as the glue will cause it to expand. The additional tightness for the mount comes from the engine clip when it is installed.
Some Mounting Kits will come intentionally a little tighter - usually on high power mounts. This is from feedback from users who prefer a tighter fit. This also allows variations in humidity and elevation. Toronto has an elevation around 300'/ 100m.
Less is More
Less glue and paint means the rocket is lighter allowing for a higher flight.
White vs Yellow glue.
White glue is more than acceptable for assembly of the rocket kits on this site ( unless noted.) Yellow glue, also know as carpenter's glue, has the same strength as the white glue. But since it is made for the wood industry, it has additives to make the 2 pieces bond initially faster - more tact. In rocketry, this will cause components to join, permanently, once they touch.
Hot Melt Glue
Do not use hot melt glue in any kits from Sunward as it is not strong enough and will tend to stretch.
Plastic Nose Cone Painting
After assembly, clean the nose cone with alcohol or cleaner. Then use extra fine sand paper should to remove all glossy areas before painting. If any gloss remains, it may cause the paint to flake.
A second method is to prime the nose cone. This may be done with primer available from hobby stores. ( Primer will say it will adhere to plastic.)
Balsa Nose Cone Painting
Apply a sanding sealer, and then sand. Repeat as needed. Make sure the sealer is compatible with the paint you are planning to use.