Gabriel;
I went and looked at one of those Italeri kits in my stash - a Flak 38 on a half-track... Sd.Kfz.10/4 or /5 - and yeah, those shields would work for a Tiger!
OK - I wanted "thin" and went with Evergreen's 0.010 styrene sheet. This would equate with a shield about 1/35 scale 0.35 US Inch, or about 9mm, thick. If you want a little more robustness, use the 0.015 sheet, but I think the 0.010 sheet would be closest to the real thing. Either sheet will come across very very nicely when tricked-out with the rivets, etc. - the more so because there will be no tapered edges and thickly-armored middles!
As suggested earlier this thread, use your Italeri shields as templates for the shapes. IF you shave those rivets off them, you can use those to "decorate" your new Evergreen plate. The trick to getting those rivets into the right locations is to draw or photo the originals so you have a handy reference pic to look at as you transfer bits.
PS: I wish I had stuck to it and completed the scratch shields for my posted gun - in the end, I put a lot of time into fiddling other details on it and adding a metal barrel... it would have been worth the extra effort to complete the shields... I saved them and will use them on some future build!
Take your time, be patient, and Good Luck! Hope to see your gun posted when done!
Cheers!
Bob