I've went to ridiculous lengths on an old R700 BDL walnut stock. Easily floated a Bartlein 3B when I was done.
I don't think you'd hurt a Tikka stock. If you got carried away and the forend felt weak you could shorten it an inch or two and reattach a sling swivel further back, in epoxy. Or perhaps epoxy an aluminum arrow shaft into the bottom of the channel to stiffen it.
I had to hog out a Boyd's laminated stock a lot for a muzzleloader once and when I was finished I epoxied an arrow shaft into the ramrod channel. That was more for making a way to hold a ramrod, but the concept seems to work.