Hi Mark
Before we start:-
Which rifle are you using? Are you using a moderator?
30-06 is a "big-ish" gun & has quite high recoil so the following are more important than with lighter kickers.
How good is the bedding of the action? & Is it tightened down properly?
Is the barrel fully floated & clear of the stock? (even with bipod on)
Is the scope in good nick & fitted right with all screws nipped up?
Next
Have you shot tighter groups with any other ammunition?
Has the bore been deep cleaned recently?
Shoot your test groups from a really good rest - rifle fit, hold & ergonomics really matter when doing load development.- Especially with big rifles!!
How fast do you want to go? 2800 is a good speed - much more will start to give you meat damage (general rule of thumb - not specific to SST bullets)
Did the rounds you shot with 51grains of powder show any pressure signs?? That is max load as per the Hodgdon data. If not you could go up a bit but I normally find best accuracy comes with about 96% of max powder loads (both 308 & 30-06) so about 49 grains might work.
Your idea of a few steps to get into the ball park is right - then when there, you could play around with bullet seating depth to fine tune it. Start long, with enough seating depth to give about 3mm minimum neck contact, shoot a group then push the next ones in a bit more - I'd go 1mm deeper then shoot another group - etc etc--- each time looking for pressure signs. With luck you'll see a sweet spot & that's where to be!!
I think there is no real short cut - you may get it right easily but your rifle may just not like your current bullet choice. You have to play & see!!
Ian
(p.s. Have you grown a bit of facial hair?? - or did you change your piccie???)
Edit - +1 on wot Muir said whilst I was two finger typing my post!!