I'll drop of a few things of TF2 I know. I'm not good enough to help on specific classes but I can provide some assistance on how to get better fps and smoother gameplay.
First of all make a backup of your tf folder (X:\Program Files (x86)\Steam\steamapps\yoursteamid\team fortress 2\tf) so that in case you don't like any of the suggestions here you can easily revert back. Just Copy and paste it elsewhere.
FPS
TF2 is a CPU intensive game and depends a lot on your clock speed so the better CPU you have the better your FPS. With my Overclocked config (see sig) I easily get 120 fps in 6v6, 8v8 games and 70 fps in 12v12, 16v16. Without the OC I would get 100-110 fps and 40-50fps respectively. So if you know your way around Overclocking your CPU you will see a significant improvement in FPS.
TF2 supports two directX modes i.e. DirectX 8(DX 8) and DirectX 9 (DX 9). By default DX 9 will applied to your system. While out of the two DX 9 is clearly better as the graphics are much better and shiny but it is also a little heavy on resources. Shifting to DX 8 will see a significant drop in graphic quality but it also helps increasing FPS. The major reason I like DX 8 is that I find the whole game much clearer and graphic quality of Pyro's fire and Soldier's Rocket Trails, Demo's Sticky Explosion,etc gets reduced which in turns helps me finding my targets with sniper (my fav class) much more easily. Plus TF2 with highest settings is no big treat to the eyes so I always play with DX 8.
DX 8 -
DX 9 -
How to change DXlevel -
Open Steam
Goto Library
Left Click on tf2 and select properties.
Select Launch options.
Enter "-dxlevel 81" for DX 8 or "-dxlevel 95" for DX 9. In the text box.
There are a lot of various configs you can apply to improve FPS. The best one I found was from a played named Chris from EU. He has a wide range of configs which can be found here
Chris' FPS Configs for TF2 | Home. He basically has 3 configs
MAXFrames - Lowest Graphic Quality and highest FPS Gain. DX 8 required
HighFrames - Low Graphic Quality and significant FPS Gain. DX 8 required
DX9Frames - Same as Highframes except its for DX 9.
HUDS
Heads up Display. I personally find the default HUD too much clattered therefore I used custom made HUDs from various other players. I'll link a few of them here check out the screenshots and see whether they are too your liking.
M0rehud - One of the most Oldest and widely used HUD.
Michaelll-hud - Similar to M0re's. see log on there page for comparison between the two.
Garm3n TF2 HUD
PVHUD - ozfortress
You can check this link
HUDs and Configs » Forums | ETF2L for more custom HUDS.
*** TL;DR *** For the lazy ones there is a very neat app where you can go crazy creating various configs very easily. Give this a try if you find above suggestions too cumbersome to follow
TF2mate - TF2 config generator
Hit me up on
Steam if you have any doubts