Wanting to do a 3000 graft session after having mulitiple ht sessions may not be an option but you certainly can put it up as a possibility to discuss with your doctor. It'll depend upon your laxity and density. The risk for wider scar on a 3000+ graft case is present on a "virgin" patient, so the likelihood on a repeat patient is more likely, as you are aware.
The other option of around 2000 size session might be something to consider first before the 3000 gr session or grafts + fue session for number of reasons:
1) you won't have to shave down in recipient or donor so virtually no downtime
2) you're not really bothered by hair loss to back 1/2 so why try to have what 3000 grafts would achieve?
3) You would be able to set aside a small portion of grafts from strip to plant into the lower donor scar so another session is not require.
4) healing time for fue sessions are almost nonexistent (few day), however, regrowing your native hairs may take several months to return to your normal length.
5) Costs much less
I personally think HT surgery is for those who are extremely bothered by their hairloss. So, if it doesn't bother you, why not put it off for now. You can still come by SMG to say "hi" and for a hug from one of the coolest chicks you know. :::C (and I'm not referring to Jill)