You'll enjoy your 7mm08.
I too am quite fond of the Sierra 140gr GK.
The 4350 (I'm assuming IMR4350) will fill the case before you reach max pressures. Even with that though, you'll probably find that accuracy is best at 46.5gr which is a compressed load, but not max.
I get about 2,750fps with that load and accuracy is the best my rifle is capable of. It just about duplicates the factory loads but with better accuracy.
My best friend used my Rem M7 to take a nice 1,100lb 6x6 Bull elk in '05. I sent him with 30rds of 140gr GK and 20rds of Nosler 140gr Partitions and above load. The Sierras were for practice and checking zero at hunting camp. He ended up mixing the ammo (expected, he's a shotgun shooter hence need to borrow an elk rifle) and ended up putting three Noslers through the elk (heart-lung, good hits), and a single SGK ended the elks struggles with a shoulder shot penetrating both shoulders and remaining balled up under hide on far side. 250yd shots. First shot to heart-lung would have been sufficient but guide said keep shooting..... Elk looked like swiss cheese. Everyone in hunting camp wanted to trade rifles with him (11lb magnums vs 7lb Remington 7mm08 that gave indistinguishable performance....)
I also like 44.0gr of Win748 with the 139gr Hornady's (flat-base, boat-tail, or SST). It's not quite as accurate as the IMR4350 load (but still sub-2moa) but velocity tops 2,800fps from the 20" bbl. This load may be too much for the 140gr Sierra's, however as the Hornady's have much shorter bore contact surfaces. Start at 40.0gr and work up with your rifle.
My efforts with IMR4064 were unremarkable. Velocities topped out at high 2,600's when pressures got high. However, I've read that most 7mm08's like 43.0gr of 4064 with the Speer 130gr bullets with superb accuacy.
Next time you buy some powder, though, get Reloader 17. It's the new Gold-Standard in the 7mm08. I'm getting 2,850fps and accuracy equal to IMR4350. I've seen 2,900+fps but accuracy isn't as good. It's really remarkable how close this cartridge is to the .270wcf but with a lot less powder.
Good luck with you efforts.